The Blog

Fall Palette Painting

By Melanie Fox

We love the views of Fall. Colors deepen or blaze and while lush floral displays are gone, strong textural compositions emerge in all their simple strength. The true bones of our garden shine as we notice combinations of evergreen textures of trees, shrubs and perennials. This is a combination that reminds us of a modernist painting, relying on textural contrast and a limited palette to great effect. Hellebores combined with Heucheras, Heucherella, Liriope, Ophiopogon, and evergreen ferns can become subtle works of art in a shade garden. Just as we see different nuances in paintings as viewed over time, some of these plants change dramatically from their Spring and Summer hues further enriching the viewing experience. So put on your jacket and stroll into your Autumn garden to see the art unfolding.

Caterpillars can wreak havoc on a vegetable garden. Cole crops (Kale, Cabbage, Broccoli, Cauliflower) can take a nasty hit from these pests this time of year. If you’re experiencing this issue you might be asking yourself “How can I get rid of them?” and “Is there an organic remedy?”. The answer is Bt.

Bacillus thuringiensis (Bt) is a naturally occurring bacterium common in soils. This bacterium operates like a virus which paralyzes the insect’s digestive system once ingested. The infected insect stops feeding and expires within a few days.

Application is a simple process. Bt is available in powdered or liquid form and should be applied to the foliage thoroughly. Early morning or evening is the ideal time for application as Bt is susceptible to degradation to sunlight as well as rain. We recommend an application about every week if necessary.

Bt should be stored in a cool, dark place. There is no need to buy more than you would need for one season. The effectiveness of the product should reduce for a couple years or so, but can be quicker in liquid forms.

Fall is for Planting

You may ask yourself “Is this a good time of year to plant?” and we can assure you that fall is an ideal time of year for planting.

The hot summer temperatures have finally subsided and things begin to cool down. You have no need to worry about your plant stressing from the heat of the summer. The cooler temperatures result in less foliage production and energy can be spent on establishing a hardy root system.

Soil conditions remain warm in fall and present another excellent reason to plant. The warm soil temperatures will encourage root growth to establish a solid root system before the winter arrives. Roots will continue to grow and develop until we hit 40°F. We highly recommend applying a layer of mulch to help protect the root system from the cold as well as retain moisture.

Rainfall may be sufficient this time of year, but we’ll never know until it happens. Provide your plants with a good soaking once a week until you turn your water off. This will give your plants an advantage against the water loss from those cold winter winds and sunshine.

 Some of the most beautiful and unique plants around the nursery are the ones that may not be the first ones to come to mind. A great example of an underappreciated tree is the Trochodendron aralioides or “wheel tree”, native to Japan, Taiwan, and Korea. Its name comes from the Greek words “trochus” which means wheel and “dendron” which means tree. The tree was unavailable to Europeans until the mid 1800’s and only then was it given its name as it began to be distributed outside of Asia.

The T. aralioides is a species of the Trochodendron genus, which is monotypic, meaning it is the only living species in its genus. It normally grows from eight feet in height and can range from ten and twenty feet tall at full maturity, rarely growing largely in width. Contrary to its habits in nurseries, it has been recorded that in the wild the Trochodendron has been able to grow up to sixty feet.  It has beautiful inconspicuous green flowers that bloom in May in the Northeast, forming small wheel-like flowers that mix with its evergreen foliage.

The Trochodendron is fortunately a xeric tree, meaning it doesn’t require a lot of watering or care. It prefers to be in a shady spot where it can be protected from winter sun and excess amounts of wind. If you put this very adaptable plant in a relatively shady area with well-drained, slightly acidic soil, you will be rewarded with a unique and beautiful bloom in the spring. 

Our designated trough-making season started and we thought it might be fun and informative to ask you miniature plant fans for input on our production. Each year, we generate a "goal list" of shapes, some created in our standard molds, and some on one-of-a-kind sand molds where our imagination (and gravity!) is our only real limitation. We have an aesthetic standard to which we adhere and we keep a practical eye on things like tolerances, widths and usability. This simply means that:

1. We do not produce "Lucky Charms" (no clover leafs, hearts, donuts or daisies).

2. The construction of the piece must be strong and plant-friendly.

In the past, we have produced a number of custom-made troughs to the design and dimensions of our clients. We have also, on occasion, been asked to fill a "wish list" for a certain number of shapes, such as small cylinders, to be ready for spring.

So we would like to invite you, our trough gardening public, to weigh in with your ideas. Is there a shape we have not thought of? Are you looking for troughs of a certain size? We are open to producing a custom trough if you have an inspiration. Let us know! We will definitely need to have a conversation about the idea you have, and the logistics of making it. We will also need a down payment if we decide to go ahead. You may have a corner that will be perfectly completed by a certain-sized triangle, a spot that needs a tall tower, or a setting on a wall that cries out for a long narrow "window box."

Trough-making is underway, and we are finished with production just before Christmas. We would love to hear your thoughts! Contact Lori Chips at 203-259-5609 or [email protected].

By Lori Chips

The best way to care for your trough as we approach winter will depend on what you have growing in it, and where you have it placed in the garden. For plants that are highly sensitive to wet, especially those with silver foliage, it can be a good insurance policy to provide some overhead cover. This can be as simple as tucking the trough under the house eaves or as complicated as building a special hard plastic roof to fit over it. Do not encase the container in soft plastic, however, as that can do more harm than good. Allow plenty of air circulation for alpines, even in the colder seasons; these plants come from high, windswept elevations, after all.  If your trough contains dwarf conifers, be aware that many can be prone to winter burn and dehydration if in an exposed position. Chamacyparis and upright junipers like J. communis 'Compressa' can be martyrs to this especially. A general recommendation is to see that your trough is not in a wind tunnel, nor situated so that it will bear the brunt of a southern exposure. Sun reflecting off of snow can also do damage. Almost everybody has a foundation planting or a shrub border facing in a gentler direction, and this would be ideal.

In some cases moving a trough or troughs can be a hardship or just too much of a project. Here at the nursery we try to get most of them down off their bricks or blocks, but some are simply too enormous to move. Breakage most often occurs while moving them, particularly venerable old ones; and the decision to let them be is the right one. (I will never advocate leaving a trough up on a windy deck, but one must be realistic about how "heroic" our measures will be.) There happens to be a very skilled and knowledgeable chapter of the North American Rock Garden Society (NARGS) located right in Manhattan, and they have no choice but to garden on balconies and rooftops. Having seen their work, I can attest to its success!

When the frost has settled in and the perennial garden is shifting toward hibernation, it is time to pull out the pruning shears and clean up. This does not mean that you clear cut the garden from one end to the other. The seeds of numerous perennials, like Echinacea and Rudbeckia, are an excellent food supply for the birds and can remain standing. Ornamental grasses and many varieties of Sedum offer terrific winter interest. These can be cut back in spring as new growth emerges.  Start your fall clean up by disposing of, rather than composting, any diseased or mildewed portions of the plants. Then judiciously prune the remaining plants, taking into consideration what type of perennial they are. Perennials fall roughly into three categories, making a difference in how they are treated in the fall.

Truly herbaceous perennials are those that die back completely to the ground. Plants in this group include Peonies, (but NOT woody Tree Peonies, which will die if cut back), Phlox paniculata, and Hosta. Be careful when raking up spent leaves that the 'eyes' or  leaf buds that lie below soil level are not damaged. The dead stalks of the plants can be cut to 2-3" from the ground. (Figure 1)

Semi-evergreen plants are those that hold a rosette of green basal leaves though the winter. The browned stems of these plants can be removed just above that green crown of leaves. Salvia, Heuchera, Achillea, and Leucanthemum are among those considered to be semi-evergreen. (Figure 2)

The third group is made up of perennials with evergreen foliage. These should only be trimmed of broken or diseased portions. Plants of this group also add winter interest with their color & form. Evergreen perennials include Lavendula, Helleborus, Iberis, Euphorbia and Dianthus. (Figure 3)

Gardens that are tended to in the fall will be pleasing to the eye through the winter, and will rebound with health and vigor in the spring.

Dressing up an existing retaining wall

By Lori Chips

As anyone who has fallen for their charms soon knows, alpines and rock garden plants can be tricky to please. One good way to accommodate them is by planting them vertically in a stone wall.  This ensures excellent drainage and a cool root run, and helps keep excess moisture away from their sensitive crowns.  And it can also be very beautiful.

When the wall garden at Oliver Nurseries is in bloom in spring, we get a flood of questions asking how to achieve a similar effect.  I would like to focus here, not on constructing a wall, but on ways in which an existing one can be adorned with plants. Living as we do in an area rich in old pasture walls, some dating back to the Revolutionary War, folks wonder if these walls can be simply planted up.

Unfortunately, the answer is no.  Although I’m not a strict adherent of the dictum “plant as you build,” I do believe it is the absolute best way of achieving survival and success.  The reason these old walls are not promising is that they are literally riddled with gaps and air pockets and chipmunk runs – not a good environment for plant roots.

Although rock garden plants often measure only a few inches across and even less than that in height, it is quite common for their roots to extend a yard or more.  If they hit dead air spaces, or worse, are afflicted by small burrowing creatures, they will simply die.  The good news is that if the wall in question is a retaining wall, it can be planted with a bit of tinkering and patience.

Getting started

Before beginning, be sure that it is a dry wall, that is, one built without mortar.  And for future maintenance sake, eradicate any weeds that may be present.  Next, determine the exposure – full sun gives you the greatest number of plant choices, and the bulk of these are sun-lovers.

There are a few good tricks for planting an existing retaining wall.  After choosing a crevice, do a little excavating.  Old kitchen spoons, crevice trowels, a dandelion weeder, and even chopsticks are handy tools. Choose small-sized plants, the bigger the root ball the more you must wedge in; besides, youngsters generally establish better.  Have ready a basin of warm water in which you’ve soaked some long-fibered sphagnum moss.  Unpot the plant, tease out the roots a bit, bandage the whole root ball with some of the sphagnum moss, and insert the plant into its crevice.  The moss will act as a wet nurse as the plant gets established.

Always add soil after the plant has been inserted, not the other way around, or the soil will simply wash out.  This can be a tricky procedure, but the kitchen spoon and chopsticks come in handy again.  A couple of small stones can be wedged in around the crown of the plant to help hold it in place until the roots get well anchored.

Planting Tips

Choose a cool or overcast day for planting. Nothing wilts plants quicker than a sunny day with a dry breeze. Needless to say, the optimum time of year for a project like this is early to mid-spring. Summer is just too stressful and in the fall we run into the threat of frost heaving if the roots have not had sufficient time to grow.

Seeding a stone wall is another possibility, or plan for plants to self-sow.  Locate columbines, for example, at the top of the wall to encourage this to happen naturally. The same applies to Corydalis lutea. Seed can also be blown into wall crevices.  Moisten the area first, then place seeds in the crease of a folded index card.  Direct the “V” to the desired spot and blow gently.  Select species that are easier from seed for your first experiments, and be aware that not every seed will germinate.

Another trick for planting an existing wall is to lift off a few of the capstones.  Remember, cascaders flow downwards so situating them up near the top of the wall will have a good effect.  Strive for random placement and try not to place cascading plants directly above other plants.  Once the top stone is off, add a thin layer of soil, unpot the plant and tease out the roots.  The sphagnum moss strips are not required here, as this method is exactly the same as if you had been constructing a wall and planting as it was built.  Spread the roots out in a fan shape on top of the soil, positioning it so that the crown is at the edge of the rock below or just a little bit further in.

                            Finishing touches

Spread another thin layer of soil over the roots and replace the capstone. Often this stone will now be a bit higher than the others so some tinkering is necessary. To avoid the problem altogether (although it is a bigger project) one can remove all the capstones and set them aside. Plant in the desired spots and add the layer of soil to the entire course so the capstones will be even.  Do not wait too long to water the new planting.  Irrigation is probably the most critical issue for a newly planted wall.  Use a gentle rose on a watering can, or a fine-holed water breaker on the hose. Try not to direct the stream at the face of the wall; this can flush out soil and even dislodge small plants. A thorough soaking behind the wall will eventually seep down and out to the roots.

Depending on the weather, I like to water a new wall every few days for the first couple of weeks and at least once a week for the first season after that. The goal is to give the roots a chance to delve deep. That Holy Grail known as, “Soil that is moisture-retentive but well-drained,” is probably epitomized best by the habitat of alpine plants.  In nature they live on sometimes shifting gravely screes and talus slopes, or in stony crevices. Their crowns stay dry, but their ambitious roots travel deep, in a moraine they will even reach constantly flowing melt water from the receding snow.  Although these conditions cannot be duplicated at sea level, many rock plants will thrive in a wall crevice.

Don’t forget that the top of the wall is a great place to show off dwarf conifers and other small shrubs, as well as rock plants that are cushions or mat formers.  In today’s smaller gardens, the planted wall offers an opportunity to protect these small treasures and to display them beautifully.

                       RECOMMENDED PLANTS FOR WALL GARDENS

Sun

Alyssum var.                                          Campanula portenschlagiana              Gypsophila cerastioides Any Aquilegia                                            cochlearifolia                                       Origanum rotundifolium types, Arabis androsacea                                   garganica                                                 such as O. ‘Kent Beauty’ Aubrieta libanotica                               Chaenorrhinum origanifolium             Origanum pulchellum Aurinia (formerly Alyssum)                Gentiana cachemerica                           Phloxes    saxatile                                                Geranium dalmaticum or                      Sempervivum Antennaria                                             G. sanguineum ‘Nana’                            And many others …

­

Part-Shade

Androsace x millstream, A.                  Corydalis flexuosa types                     Hutchinsia alpina   sarmentosa, A. sempervivoides        Cymblaria var.                                       Lonicera crassifolia Aquilegias                                                Euonymous ‘Kewensis’                        Saxifraga trifurcata and other   Asarina procumbens                             Ferns (smaller types like                         mossy saxes Calluna foxii nana                                     Aspleniums and Woodsias)                Sedum nevii (a small native    Chiastophyllum oppositifolium          Houstonia (Heydyotis)                             sedum, will flourish in shade) Corydalis lutea                                         caerulea                                                 And many others …

A few exceptional choices for your fall garden...

PINUS densiflora 'Oculus Draconis'   Dragon's Eye Pine Conifers have a particular sparkle in the fall and this pine is eye candy on clear autumn days. The bright yellow banded needles are stunning from September on through the winter.

LESPEDEZA thunbergii 'Gibraltar'   Bush Clover Extend the bloom in your garden with these rounded shrubs. They are cloaked with small pea flowers of deep rose purple from late summer through October.

LAGERSTROEMIA Crape Myrtle Tree like shrubs bloom in late summer, but the show continues into the fall with shiny, orange-red foliage. The exfoliating bark on multiple stems is terrific throughout the year. New hybrids are hardy to Zone 6.

ARONIA Chokeberry We have a wonderful selection of these native shrubs that are in their glory in the autumn. The glossy foliage glows in shades of red and purple. The edible fruit persists into the winter. This is a very useful plant for naturalizing in moist soils.

By Paul Janisch

During the "off" months of winter we as gardeners have a chance to make an assessment of our surroundings. With the copious rainfall we received this year the plants responded with vigorous and at times surprising amounts of growth. In our assessment, there are times when we realize that some plants have gotten out of hand and need to be scaled back. Now is a good time to do this.

           Deciduous trees and shrubs have dropped their leaves making the branching structure more visible. The way is clear to make the right decisions as to what should be cut and what should remain. There are three basic steps to follow while pruning. First, cut out any dead or diseased wood. Second, remove any crossing branches that would interfere with future growth and third, prune to shape the plant with an eye to the overall aesthetic. Never remove more than a third of the total tree or shrub and take your time. Think before making each cut, once it is done it can't be put back.

A couple of things to keep in mind; if the shrub is spring blooming, in the process of pruning you will also be removing flower buds. Prune only as necessary unless there is a reason to prune the shrub back drastically and bloom is not of consequence. Trees such as maples, beech and birch have a tendency to "bleed" from pruning cuts. Therefore it is far better to complete pruning on these at the beginning of winter, giving the cuts a chance to season or heal before the sap flows in spring. The experts tell us that pruning when the wood is frozen is not a healthy practice. Making cuts on very cold days can damage cells in the frozen wood and proper healing will be hampered. So save your pruning for a nice sunny day that is above 35 degrees.

As in any task, the condition of the tools you use makes a big difference in the success of the job at hand. Keep your pruning tools clean, sharp and lubricated. Hand pruners are perfect for any branch smaller than your thumb, loppers can be used on branches up to the size of a rake handle. Branches larger than six inches should be tackled with a sharp bow saw or chainsaw. Making clean cuts as you prune is as important as making well chosen cuts. It is only with well maintained and sharp tools that this is possible.

Never prune just for the sake of pruning, a bit of advance research on the growth habit of your plants will be helpful. Now is the time to enjoy this less hectic gardening season.

By Jim Gerrity

As you may or may not know, Oliver Nurseries offers landscape design services. Knowing where to place a plant on a property is just as important as choosing the right plant. No matter how beautiful a plant may be, if it's in the wrong location chances are it will not have the desired effect. That's where we can help. Over the years, I have been asked to fix many landscapes that just "don't seem to work." The reasons vary, but often they share a common mistake, lack of planning. Too often, only a plant's aesthetic value is considered before a purchase. The growing requirements of the plants, their ultimate size, and, most importantly, the problem you are trying to solve should be taken into consideration as well .

I've often found myself asking, "Why did you plant a weeping cherry tree three feet away from your house?" In order to maintain a tree, wanting to get 30 feet tall and wide, in that spot will require a lot of pruning. The response most commonly given reflects on the lack of planning mentioned above, "Because when I planted it there three years ago, it looked great." I would have suggested either choosing a plant more appropriate for the size restrictions, or planting a weeping cherry at least 15 feet away from the house to allow for full growth.

"What are those brown twigs under your Pine trees? Oh I see, those are the remains of some unfortunate shrubs. What were they doing there?" Sadly, I have seen more plants subjected to this type of slow torture than I can bear. Without water and sun a plant cannot survive. Unless your plant is guilty of some unspeakable offense, planting it under a pine tree, which shades all direct sunlight and sheds away the rain with its canopy, is the equivalent of a death sentence.

Now, I know these are some extreme examples of mistakes, but the point that I'm trying to get across is that you should know what you need before you decide what you want. If you have nothing but shade in your yard, sun loving plants are not for you. If your property is small, then planting a tree that can grow very tall and wide is probably a bad idea. The better way to decide on what to plant is to assess what your needs are and then seek out a plant that will address your concerns.

Start by evaluating your property. Is there a bad view you want to hide, an attractive view of your neighbor's well maintained perennial garden that you want to appreciate, or is your house too large on the outside to relate to human scale? (This is the most common and the most unrecognized issue in my opinion). The list goes on, but the point is that you need to find the problem before you can find a solution.

As you start thinking about next season and your next project, please feel free to give us a call so we can help you develop a plan. We'll not only help you choose the right plants, we can also propose a landscape plan for your whole property, including hardscape components such as masonry and driveways. Please don't wait until you realize your landscape solution "didn't work" ... give us a call.

By  Melanie Fox 

Last week, I signed up for "Helleborus Anonymous," one of the numerous plant addiction support groups available for the horticulturally challenged. Now, when I say challenged I mean that my ability to resist being fascinated/obsessed with particular groups of plants is often not what my horticultural counselor would wish for complete health. When asked to pen an article on my perennial plant selections for 2012, like any plant addict worth their salt, I immediately gravitated toward one of my obsessions: hybrid hellebores. I am addicted to the wonderful variety of their flowers, fabulous evergreen foliage, and ease of culture, and the generous way they reward even a sometimes negligent gardener. A negligent gardener who might perhaps purchase a few more beautiful hellebores than she can plant in a day! Three outlines and six pages of notes later, I realized that an article about our upcoming hellebore beauties was going to require extraction from an immense subject matter. Since conquering an addiction is about making choices, I decided I can't love them all, buy them all, or describe them all in one article.

I decided to focus on the two best known hellebores, commonly called Christmas rose and Lenten rose, due to their respective bloom times. Christmas rose generally refers to Helleborus niger or selections of this plant. Before the advent of the Julian calendar, Christmas was celebrated on January sixth which is about the time H. niger begins to bloom despite the adverse weather. In the wild, Helleborus niger can be somewhat shy flowering, making each bloom a much anticipated event. However, modern selections from thousands of seedlings, and the use of tissue culture propagation techniques, have ensured that many flowered clones and even double-flowered forms are readily available. Heuger Nursery in Germany has concentrated a large part of their breeding efforts on Helleborus niger and Helleborus x nigercors selections. Helleborus Gold Collection® varieties H. niger 'HGC Josef Lemper® and H. niger 'HGC Jacob'® are from their program. These two selections have an abundance of large white outward-facing blooms held in a stunning array.

               Helleborus x nigercors is the result of crossing H. niger with H. corsicus (now known as argutifolius). A number of fine hybrids emerge such as H. x nigercors 'Honeyhill Joy,' with its glossy green foliage and large clear greenish-white flowers that bloom well into April, making it one of our new favorites at the nursery. Another group of niger hybrids is H. niger x H. lividus known as Helleborus x ballardiae. Two introductions look particularly interesting: H. x ballardiae 'HRC Pink Frost' and the H. x ballardiae 'HRC Cinnamon Snow'®, and I plan to trial a few. 'Pink Frost' has beautiful silvery venation on the leaves, so even without its pink blooms it makes a beautiful addition to partial shade. 'Cinnamon Snow' has large white flowers that develop a rosy cast, which then turn cinnamon as the flowers age. The attractive dark green foliage reflects the influence of its niger parent, providing a clear foil for the flowers.

Before I jump to the balmy weather blooming hellebores, the Lenten roses, I should mention Helleborus foetidus, a somewhat forgotten hellebore species which actually blooms before and after Christmas. H. foetidus suffers from the unfortunate appellation "Stinking Hellebore" which is untrue as neither its leaves nor flowers possess an unpleasant odor. Instead, its leaves are a wonderful intense green touched with black, and form an elegant lacy canopy which sets off the clusters of small chartreuse bell-like flowers. Although not as long lived as Helleborus x hybridus, which can persist upwards of twenty years, H. foetidus makes up for its brevity with an ability to re-seed at the base of mature plants. In my garden, I have an H. foetidus colony which I leave largely undisturbed. In the chill of late November when my garden is neatly-trimmed stubble, I take comfort in the evergreen persistence of H. foetidus already forming clusters of buds in preparation for a miraculous display of flowers in December. Frigid temperatures and snow may bow the plants, but they bloom on, proving we can have year-around bloom without a tropical climate. I'm not sure who pollinates these brave blooms as I have never seen bees in parkas, yet somehow my colony forges on. From year to year they cheer me up during the horticultural doldrums and tide me over until my Helleborus niger are ready to perform. Helleborus foetidus has a few nice selections worth pursuing, albeit somewhat elusive, such as 'Wester Flisk,' with red petioles and a red margin on the chartreuse blooms, and 'Sopron,' a robust form almost shrub-like, and 'Silvertooth' with a silvery cast to its foliage.

               On to the Lenten roses, which owe their common name to the flowering period of March through April, which coincides with the Christian observance of Lent. Helleborus x hybridus, as it is now called, is a fascinating and diverse group. About ten years ago, most commercially-available hellebores, excluding straight species, were sold under the umbrella of Helleborus orientalis, and followed by the cultivar or seed strain name. Those names were a bit misleading as they likely had one orientalis parent, but might have had Helleborus odorus, torquatus, pupurescens, or atrorubens in their lineage as well. Now, Helleborus orientalis is reserved just for that species, not common in gardens or the nursery trade. We have H. orientalis to thank for the large, dark, mostly evergreen leaves of Helleborus x hybridus selections; the bold texture of their broadly palmate leaves serves as a counterpoint to finer foliage in many areas of my garden.

Culturally, H. x hybridus is an undemanding plant. It adapts well to dry situations, but is more vigorous in well-drained garden soil, and it's not as pH specific as Helleborus niger which likes a more alkaline soil. In early March, I cut back any winter-tattered foliage which allows me to better see the blossoms, which on my mature plants can be more than 50! As my life has grown more complicated, the undemanding character H. x hybridus has caused me to include many more of them in my garden. My faith in those 30 three-inch seedlings planted nine years ago has been well rewarded - they are now the backbone of my front garden and have persevered despite scant attention. All my plants are all from a well known seed strain Helleborus x hybridus Royal Heritage™ which was developed by John Elsey when he was at Wayside Gardens®. I find all of my plants beautiful, but the world of hellebore breeding has slowly steamed on and marvelous new forms are now available.

In the past, Europe dominated the hellebore hybridization market, with names like McLewin, Ballard, Strangmann, and Smith on every hellebore collector's tongue. The full names of some very popular, widely available hybrids such as Helleborus x ballardiae, and H. x ericsmithii 'Ivory Prince' bear this out. All serious hellebore breeders possess plants from the lines created by these famous names. I should mention that anyone who attempts hellebore breeding, by definition, is serious and patient, as only 20 percent of seedlings bloom by their second year. A plant needs to flower to be assessed as to its merits for inclusion in a breeding program and some plants can take up to five years to flower. Some crosses are sterile and need to be put into tissue culture to make them commercially available. Helleborus x hybridus is divisible, but this is too slow a process for today's market. Therefore, many breeders concentrate their efforts on developing hellebore seed strains, refining them to the extent that the plants come 80-90 percent true from seed. A case in point is the exceptional white Tasmanian double, 'Mrs. Betty Ranicar,' which has an amazing 98 percent true doubling from seed, a benchmark for breeders around the world. The cost to the breeder, and thus eventually to the buyer, is lower as they can market unbloomed seedlings faster. So as a buyer, you should be aware that you are most likely purchasing a plant from a seed strain, and with it comes a 10-20 percent chance of genetic diversity. The German hellebore breeder Gisela Schmiemann's very popular 'Lady' series, which was selected for certain flower colors, is a seed strain, although labeling makes it seem like the plants are clones. Ms. Schmiemann is internationally respected, and carries on her work using plants produced by the late Helen Ballard, a famous English hellebore breeder. A seed strain does not mean that the plants are inferior, just that there is a chance there will be variations. If you want to be sure about what you are buying, purchase a blooming specimen or a tissue cultured plant which will be a genetic copy of its parent.

Hellebore fever has spread to the Americas and is often the work of an enthused collector who becomes entranced with the possibility of developing yet another perfect blossom. We have several notable breeders here in the United States: Barry Glick at Sunshine Farm and Gardens in Renick, West Virginia, has produced the Helleborus x hybridus 'Sunshine Selections' as well as the stunning Helleborus 'Sun Marble' an x ericsmithii cross which always evokes admiring comments in our display gardens. David L. Culp in Brandywine, Pennsylvania, has produced the D.L.C. hybrids which contain singles and doubles of exceptional color clarity. Judith and Dick Tyler of Pine Knot Farms in Clarksville, Virginia, work on strengthening their seeds strains known as Pine Knot Select Strain and 'Southern Belles,' which refine color and form in each generation. Breeders select for size of flowers, how the flowers are held, doubling, semi-doubling, spotting, and picotees, making the number of choices dizzying.

I am truly obsessed with hellebores in any shape or form, but my pocketbook directs me to more affordable unbloomed plants of respected seed strains. So early last year, I looked for plants to complement those offered by our regular suppliers. I slogged through international sites on hellebores and hundreds of Google® images, but found myself returning to the same pictures of stunning doubles from a breeder in Oregon. The doubles were part of a seed strain called the Winter Jewels™ Series bred by Marietta O'Byrne at Northwest Garden Nursery. The series includes primarily doubles and a few singles, all of which have a unique sparkle. I knew I had to acquire some for the nursery's 2012 perennial selections. I had a happy experience with my plants from the Royal Heritage seed strain, and look forward to a new journey of discovery with my plants from the Winter Jewels strain. My current dilemma is how to choose between them; the temptation, based on the images I've seen of the plants, is to buy them in multiples and revel in the beauty and variety of their blossoms, savoring each jeweled surprise!

Some of those Winter Jewels are: Peppermint Ice, a soft pink double, Sparkling Diamond, a stunning greenish white double, Golden Lotus, a soft yellow double, Berry Swirl, a deep pink to burgundy double, Onyx Odyssey, a deep maroon to black double; Jade Tiger, a brilliant chartreuse double, edged with burgundy; Cherry Blossom, a soft single pink; Ice Follies, a soft yellow single with burgundy spotting; and Painted strain, a lovely white and burgundy picotee.

        Next spring, no one should be surprised to see me staggering around the nursery, arms full of my new hellebores mumbling, "It's okay, just a few more hellebores... These are job-related choices and my horticultural counselor said I could pick nine new hellebores without relapsing!"

By Mimi Dekker

Contrary to some beliefs, you don't have to cut back all your herbaceous perennials to the ground each fall. Leaving nothing but pointy sticks and mulch doesn't give you much to look at. Leaving many plants up not only provides the garden with some much-needed structure during the winter, but winter birds get extra food and shelter, and your plants get some added benefits, too.

Gone, of course, are the vivid colors and foliage of warmer days, but you'll be amazed how summer's "leftover" can maintain interest in the garden all the way to spring. Such is the case with the tawny golds and fuzzy inflorescence of Miscanthus sinensis 'Adagio' or the papery blades and pearly seeds of Panicum virgatum 'Shenandoah.' The nearly-black stalks and seed heads of Echinacea purpurea and Rudbekia provide a stunning contrast against Perovskia altriplofolia, which stands up all winter in a soft, twisty, grey mound. Also, the wispy, swirling broom-like branches of Lespedeza and Sedum 'Autum Joy,' truly a winter joy, when its muffin tops are dusted with the first snow.

Absolutely, go out and clean up the detritus, and practice good garden hygiene with your herbaceous peonies which are disease prone, and with most Hosta which turn mushy after a hard frost. Better to cut these plants to the ground and take the remnants to the dump.

I think a garden full of interesting dry, desiccated plants looks a whole lot better than the stark and desolate tableau I used to leave behind. Not only do I feed the birds, but the branches and stems of perennials collect leaves which provide insulation, and keep the snow from crushing the plants.

Some perennials, such as Lavandula, Iberis, Arctostaphylos uva-ursii, Perovskia, and Teucrium chamaedrys, are actually subshrubs -- low shrubs with woody stem bases and overwintering buds. Hard pruning these plants in autumn can kill them in a severe winter. Wait until spring and hard prune or shape them down to the live wood. And, if it's a little green you want even in winter, perennials such as Helleborus, Bergenia cordifolia, and Asarum european are evergreen, only to be cut if the foliage becomes unsightly. There's a long list of plants you can leave up and prune in the spring. They are: Artemisia, Aster, Astilbe, Platycodon, Acanthus spinosus, Rudbeckia, Asclepias tuberose, Campanula, Lobelia cardinalis, Heuchera, Euphorbia polychrome, Dianthus, Tiarella cordifolia, Digitalis purpurea, Liatris, Echinops ritro, Solidago, Eupatorium maculatum, Alchemilla mollis, Stachys byzantine, Santolina chamaecyparissus, Lupinus, Ceratostigma plumbaginoides, Echinacea purpurea, Perovskia atriplicifolia, Limonium latifolium, Eryngium, Sedum, Coreopsis, Chelone lyonii, Amsonia tabernaemontana. So give your pruners a rest, and venture out that first warm day in March instead.

By Jed Duguid

A very common request from our clients is to plant screening trees. Many of us here in Fairfield County live closer to our neighbors than we would prefer. It's not that we don't love our neighbors--in fact it's quite the opposite. We love them so much we don't want to expose them to our naked morning coffee routine, or whatever. It may not be a neighbor's house we don't want to see--it may be a heavily traveled road, a shed or swing set, or perhaps a fence or a commercial building. Some people just don't like the look of the "woods" their property abuts, sometimes we like the feel of an enclosed outdoor room or perhaps it just feels nice when your yard has good privacy. And that's most often what it's about. There are many good options for screening in almost any situation.

What makes good screening? I guess the easy answer is anything that blocks or obscures what you don't want to see. More often than not you probably want something evergreen, although in some instances deciduous plants can accomplish the desired level of privacy. Either you don't need the screening in the winter or the structure provides enough to achieve the desired effect. Many coniferous plants lose their lower branches with age, so avoid species, such as white pine, that self prune and lose their capacity to screen as they mature. There are many factors to consider when choosing screening plants. Site factors such as sun, soil, and moisture availability need to be matched with plant characteristics such as density, growth rate, ultimate size, whether they are shade or sun tolerant, and if deer tolerant. The following are some of our favorite screening choices for a variety of situations.

Picea: Spruce. There all kinds of spruces - Norway, Serbian, White, Blue and Oriental among others. You need good space for spruces as most of them will get a 15-20' spread or more at the bottom (of course there are exceptions). You also need sharp drainage and over a half day of sun for most spruce to remain full, happy and healthy. Many spruce look quite dramatic with age as their boughs curve skyward. They tend to be fast growing plants putting on more than one foot per year and deer dislike most spruce. We have witnessed, on multiple properties, browsing on Picea orientalis--oriental spruce. In a large yard, one strategically placed Norway spruce (admittedly not the most exciting of plants but a beautiful majestic tree just the same) can hide a neighbor's house. If room permits stagger their positions for a more natural look, rather than a row of Christmas trees.

Thuja plicata: Western Red Cedar. Quickly becoming the most common screening plants used for a number of reasons. They are fast growing, relatively slender, upright conical trees, putting on upwards of three feet growth in a single season. They are tolerant of dry sites as well as sites too wet for most spruce to grow. They can grow in less than half a day of sun, though they will still want a few hours of direct sun. If you have a shadier site, it also helps tremendously if you start with younger plants that will be able to adjust better. They stay full to the ground for many years--even on sites where deer spend a lot of time! I have three game trails that converge in my meadow where I have a group of Thuja plicata 'Spring Grove' that help to hide a heavily traveled road. I'm not missing so much as a bite off them. The United States National Arboretum bred western red cedar with Japanese arborvitae to come up with the wildly popular interspecific hybrid 'Green Giant'. There are reports of browse damage in Westchester County on 'Green Giant' specifically, but they remain uneaten here for now.

Calocedrus decurrens: Incense Cedar (syn. Libocedrus decurrens) is a great option with an incredibly vibrant green color through the seasons. Incense cedar is a moderate grower, putting on anywhere from one to two and half feet of growth in a season. They are somewhat shade tolerant and very drought tolerant. They are not the densest of plants, but they certainly are effective screens. Deer seem to love them, so additional plants may be necessary at the base, or use them in a situation where the undesirable object is higher elevation and the lack of lower branches doesn't matter. Because they have a more oval shape, you'll get better coverage up high faster than you would with a narrow conical plant like the western red cedars. Paul loves to add cuttings of Incense cedars to wreaths at Christmas, along with the next option...

Ilex opaca: American holly. American holly is the quintessential holly that doesn't feel good when you rub against them. However, if height isn't the issue American holly is the way to go. They are slow growers putting on just six to 12 inches per year. If they are in a wet, sunny site--and they love wet--they will tend towards the latter. While deer eat many of the Japanese and blue hollies, they leave American holly alone. Songbirds, however, don't. They are also shade tolerant. The broad leaves of cultivars like 'Miss Helen' and 'Satyr Hill' are fantastic in juxtaposition to any of the coniferous options for a great textural addition.

Thujopsis dolobrata: Staghorn cedar (aka Japanese elkhorn cypress and about 20 other common names) is one of the most underutilized species in the nursery industry. Despite its name, deer are not as fond of this as you might think. It's actually a pretty fast grower putting on as much as two feet per year. It is somewhat bushy as a young plant but as it starts to gain height it becomes pyramidal and majestic. It is very sun and shade tolerant, though it does not like dry shade. It has a very coarse texture, as far as conifers go, which mixes in the landscape nicely. The only downside is they are only available as young three to four foot plants.

Thuja occidentalis: Emerald Green arborvitae ('Smaragd'). I would be remiss if I didn't mention Emerald Green arborvitae. If you have full sun and no deer, no other plant makes as nice a green screen as Emerald Green. One of the first things people notice when they pull into Oliver's is the serpentine hedge of Emerald Greens along our parking area. They remain very slender so are the perfect choice where space is not abundant. They grow somewhat slowly but are readily available from 3' to 14' and will grow to 20 to 25'. We like to stager the size in the serpentine hedge to add more depth and character. They make a fantastic foil for any bedding plants (or any plants) that you might want to plant in front of them. Just remember if plants are growing into them and shading them they may get a little loose looking at the bottom. For many years this was by far the most popular screening plant we carried. It would probably still be today, if it were not a favorite treat of deer. Emerald Greens are a perfect choice for the spatially-challenged with only a three foot width at the bottom over many years. Planting a small grouping of three--again with mixed sizes--will do the job of screening out a neighbors shed or woodpile.

Mixed border: There is no law that says you need to have a monoculture hedge if you need screening. A mixed border of conifers and other evergreens can really make a knock-out statement. You should definitely consider this option if you have a large area to screen, so you don't end up looking like you have started a Christmas tree farm. By using a few different species, it can read more like a garden. It will add some spice to your property, and provide screening at the same time. Just be very careful because if not planned well, it can look like a terrible mess!

Screening trees don't necessarily need to be planted on the property line to be effective at screening. You can use the topography to your favor. If you sit atop a hill and your neighbor sits below you with the property line at the bottom of the hill, planting trees at the crest of the hill will hide your problem much faster than planting at the bottom of the hill. It's like getting instant extra growth. Sometimes you may not need a hedge at all, one or two strategically placed plants can often block more than you think. Before investing in a large hedge take a good look at the area and see where exactly you need to screen. Bring us some photos (not on your Blackberry®!) of your sore spots and we'll help you come up with a solution.

By Mimi Dekker About a year ago, I planted a Pinus mugo ‘Montana’ in a small, walled garden off my front entrance. Along with all the other small deciduous trees and shrubs, dwarf conifers, and perennials, the mugo was looking great. That is until this weekend, I noticed a serious defoliation of the top two-thirds of the plant, literally overnight. My immediate fear was a sawfly caterpillar infestation. Sure enough, I spotted two large squiggly masses on opposite sides of the conifer, gregariously feeding on the remaining needles, below the caterpillar’s defoliation line. The scene made my skin crawl.

According to the Forest Pests website, “If infestations are light, manual removal of larvae may effectively control the pest.” Well, I don’t know about you, but picking off dozens of squirmy larvae, up close and personal, is not my idea of fun. At the same time, pesticides are not on the shelf in my greenhouse. However, I found a fresh bottle of “Dr. Bronner’s Magic 18-in-1 Hemp PEPPERMINT Pure-Castille Soap” (made with organic oils!). Purchased at an orchid show to control soft scale, I thought I’d give it a try. Two tablespoons in a quart of water is the recipe for scale, so I tried the same mix on the caterpillars. I generously showered them with the solution, and by the time I circled the mugo, the caterpillars were writhing and dropping to the ground. Within an hour, they were all but dead and I could flick their lifeless bodies off the pine.

Post-mortem is the only way I can handle looking at most insects, so I carted off a few carcasses to my computer for identification. Looking at larger-than-life pictures of insects and bugs on the Internet is not something I do just before retiring. So being mid-morning, I was all over attempting to I.D. these nasty critters.

My research started and ended with The Connecticut Agricultural Experiment Station website, where I found photos and descriptions of pine-eating sawflies in Connecticut. In all cases, the fly’s larvae can defoliate whole sections of a pine, very rapidly in late summer. Three images on the website showed:  the pine sawfly, Diprion similis, which has brown and green-striped and mottled larvae; the white pine sawfly, Neodiprion pinetum, which has whitish larvae with black spots and a black head; and the redheaded pine sawfly, Neodiprion lecontei, which has yellow larvae with black spots and a red head, which feed on white, red, and mugo pines.

The website also mentioned another species which feeds on the pitch pine, while a larger species webs together the needles and its frass to make a nest, in which it lives and feeds (gross!), on Austrian pine. But the redheaded pine sawfly was clearly the culprit on my mugo!

So what’s the good news? Because the larvae did not eat the buds for next year, my mugo will likely come back. In two weeks, I’ll spray the mugo again and keep a watchful eye for eggs and re-infestation until a hard frost. Next spring and summer, I’ll be on the lookout for the larvae as well, and will spray a little Dr. Bronner’s around for prevention.

For further Reading: Redheaded Pine Sawfly – Its Ecology and Management, US Dept. of Agriculture. http://naldc.nal.usda.gov/download/CAT92980974/PDF

For further questions on Sawfly, or a question on a different concern in your garden, email us at [email protected], including pictures will allow us to get a better idea of the issue.

            If you've read through our previous plant spotlights, you might have picked up on a theme of unique historical relevance.  Though obviously true of the previous posts, that was more of a random happening than a set out theme.  As much as historical uniqueness does intrigue us here at Oliver Nurseries, we have plenty of plants with unique traits that are just as interesting as other plants' unique histories.

            There are an endless number of plants with amazing flowers or different and unusual leaves, but few catch your eye because of where the flower is positioned. Epiphyllous (Epi = upon and phyllon = leaf) flowers have a bizarre positioning of growing from the middle of the leaf. This rare morphology comes from a fusion of the petiole (the leaf stem) and the pedicel (the flower stem) in the middle of the leaf.

            Helwingia chinensis is one such plant that carries this characteristic.  Given to Dan Hinkley by JC Raulston in the 90s, Dan was very intrigued and began a search to find it in its native area of China and then introduce it to North America.  This unusual plant is part of a monotypic family (comprising only a single genus, Helwingia), and all three species are native to the Himalayas and eastern Asia (Note: To learn about a monotypic genus, check out our write-up on Franklinia alatamaha).  Similar to Ilex (commonly known as Holly), Helwingia chinensis is a dioecious shrub, requiring separate male and female plants in order to pollinate and get fruit. 

            The rareness of this species makes it a collector's choice.  As it is in the early stages of being cultivated, its hardiness is unknown, but is assumed hardy to zone 7.  In addition, it has been hard to come by both male and female forms.  This has led to the plant being a great addition for its unique flower location and look, not for pollination and fruit. 

            An evergreen plant with medium green, narrow leaves, H. chinensis is a great addition to a partial shade area; best if planted with protection, such as under a tree's canopy, or nestled amongst some evergreens.  It is a vigorous growing shrub to roughly six feet tall and three feet wide.

            We just planted one in our garden, and it'll definitely be a plant to watch as it grows.  Never intrusive, rare, with a flower that is all but guaranteed to start a conversation; Helwingia chinensis brings a different level of beauty to any garden.

     Here at Oliver Nurseries our goal isn't simply to sell plants and design gardens, but to help educate new gardeners and veteran gardeners alike.  The approach is obviously very different depending on the level of experience someone has.  Today we are focusing on the novice and the basics of plant names.  Give it a read if you feel you are somewhere between novice and veteran, you just might learn something as well.

     In the past, new gardeners often commented that our catalog was very hard for them to read and understand if they knew nothing about plants or did not read Latin.  In an effort to make the task of selecting plants easier and less frustrating for the novice, we have added more general descriptions of major plant groups within our catalog text.  These descriptions should help educate first-time gardeners about plants suitable for their gardens and arm them with enough of a background to make them dangerous!

     The plants in our catalog are listed by their botanical names, which are Latin based. The botanical name is broken into two parts: the genus and the specific epithet. Genus refers to the major plant group and is always capitalized.  For example, apples all belong to the genus Malus.  Specific apples within this large genus are referred to by their species name (genus and specific epithet).  The specific epithet is not capitalized.  For example, an eating apple’s botanical name is Malus domestica.

     Usually, the specific epithet will tell you something about the plant. It might refer to things such as color, leaf shape or the plant’s place of origin. A short list of some common words used in specific epithets follows.

                       Within some species, certain varieties have been developed which are known only in cultivation.  These are termed cultivars and will appear in our catalog in single quotations, an example of which is Malus domestica 'Granny Smith'.  Each cultivar has particular traits similar to the species but is unique in some regard.

     Here is where it gets just a little bit more complicated.  Malus has cousins, plants with common characteristics that the taxonomists have grouped into families.  Obviously, all of these cousins do not have the same name.  Malus are related to Alchemilla (Lady's Mantle), Rosa (Rose), Spiraea, Geum, Amelanchier (Shadblow), Cotoneaster, Prunus (Cherry) and Potentilla, to name a few.  They are all members of the family ROSACEAE.

     If we look at another family, FABACEAE, the similarities become even more clear.  One could make a garden with Cercis (Redbud), Wisteria, Baptisia, Cytisus (Broom), Lupinus (Lupines) and peas and beans, and everything would fall under the same family name.  As you knelt down in the clover (Trifolium -- still in FABACEAE) to harvest your peas and beans in your blue jeans, it might interest you to know that the first blue dye came from the pea family -- the famous and costly Indigo (Indigofera).

     Family names can be a fascinating game, but they are also an indispensable tool.  The lone botanist on some Andean Alp can be confronted by a plant he/she has never seen before.  But when kneeling down for a closer look, there is an excellent chance the plant's characteristics will tell him/her to which family it belongs.

     To download our catalog, click here: http://olivernurseries.com/oliver_catalog_09.pdf. You can also swing by the nursery and grab a hard copy. Keep in mind, our catalog represents our enthusiasms, rather than being an all-inclusive list of availability.  Please feel free to ask if we have failed to list something of interest to you.  If you are traveling from far away, please call ahead and make sure we have what you are interested in currently in stock.  To join our mailing list click here: http://olivernurseries.com/mailing.html.