Plant Profile: Red Maple - Acer rubrum

If you live in America you've probably seen a red maple before, this versatile little beast is one of the most ecologically widespread and common tree species in the east.

Let's start with the name: Why is it called Red Maple? The name refers to the beautiful ruby red spring buds/flowers (Image 1: Red Maple swamp West Milford, NJ) in addition to the vibrant fall colors. Suburbanites often confuse 'Japanese' maples as "red maples" due to the leaf hue but unlike that cultivated variety, Acer rubrum has green leaves and will preform very differently, angry clients sometimes 'buy the wrong tree' then make it YOUR problem.

Red maples are very variable within their geographic range, in some forests they can occupy a dominant understory position, some they are dry mountain dwellers, while in others they are niche successional wetland species but in most cases they exist as a 'short' lived tree usually dying before 100 years of age (Image 2: 150 year old specimen, Chester County, PA). These phenological differences can be genetic quirks of an isolated population or just occupying an available place.

Quick description on how to identify: Red maples are a fast growing deciduous tree species usually free of branches for about half it's height (reaching around a hundred feet). The bark itself is usually a smooth darker grey when young becoming lighter, randomly furrowed, ridged and scaly at maturity, in wetland environments it's not uncommon to see a lime green lichen present on its bark (Image 6). Twigs are usually purplish with redder new growth (Image 4). Buds and flowers are usually fully red (Image 3) and samaras (cute helicopter seeds) have red and green tints and are quite small compared to other American maples. These trees are usually unisexual (flowers are male or female, some pollinated female flowers image 3) though some have both sexes on the same tree and have been known to change genders. The leaf of a red maple (image 5) is pretty variable in proportions but has 3 very distinct lobes (sometimes 5 lobes) and very toothy, opposite placement and will create the most vibrant red color in fall fading slowly to yellow sometimes.

Within its native range red maple has a few 'subspecies' (Swamp red maple var. drummondii whose leaf has hairy undersides and Carolina red maple var trilobum which has a smaller 3 lobed leaf) but not many look alikes of other species. Mountain maple (Acer spicatum) has similar leaves but is a shrub present in the Appalachias and anywhere north of New York. Amur maple is also similar but this is usually restricted to gardens and has a proportionally long leaf.

The native range of red maple encompasses the entire Eastern United States with a southwestern limits in East Texas and a northwestern limit in Minnesota extending eastward with a northern limit in Newfoundland. I've personally seen this tree at both limits of its range (the Everglades and Quebec) and the further south one goes the more restricted to swamps and streams, conversely the further north the less restricted to wetlands it is (Image above: Red Maple on right in Catskills Mountains).

Habitat: Red maple is relatively dominant in New England-Mid Atlantic Wetlands, every tree you see with green lichen is a red maple in the image above (Great Swamp,NJ). The key for red maple seedling germination is soil moisture, which is why the further north one goes the more common it is to find. Naturally Red Maple is not meant to be as dominate as it is, I often state colonialism influenced our modern forest cover in distinct ways. Fire suppression, Low lumber value, and Clear Cut Disturbance has allowed the tree to thrive. Early successional (fast growth/high seeding) and Late successional habits (shade tolerance) makes Red Maple a perfect candidate for 'domination'. This may seem like a looming biodiversity threat when in reality the tree regenerates forest loss extremely well, it's short lifespan and weak wood/shallow root system often allows hardier trees (in non-wetland conditions) to readily take over after several decades. Each image (above and below) I'm showing with near total Red Maple coverage was once farmland less than a century prior giving way to variable forest. Additionally Red maples are important food sources for early pollinators and it's seeds are probably one of the top early summer food sources for squirrels.

Future trends: It is unknown what the future holds for Red Maples, With climate change increasing heavy precipitation events and late spring droughts may impact seedling success, though the tree is hardy in floods and dry periods. The Image above actually just experienced a large wildfire (the image is 6 month before burn) which will likely lead to a replacement with more fire tolerant species. Red Maples have thin bark and die easily when facing predation (Beaver herbivory visible mid-left above) and disturbances. On a positive note, according to a 2022 Boston University study warming trends are increasing the nutritional content (Nitrogen, Phosphorus, etc. concentrations) of its foliage which may be good for forest soil health.

Direct Uses: Red maple is considered a 'soft' maple and is often not used for much aside from veneer. Red maples have concentrated forms of tannin and the bark can potentially be used to make dyes though I have not tried this. Of direct human consumption occasionally people will use this species to derive syrup though unlike sugar maples they have a relatively short harvest period. The leaves are also toxic fodder for equine species (and humans), so don't use this in silvopasture!

Growing Red Maple: Thousands of red maple seedlings usually take over my beds and die within the year, occasionally I'll take a sapling for my personal nursery. I've found that the tree performs extremely well in partial shade and has the potential to grow 2' a year once established. Once mature, not much will survive around the trunk due to it's shallow roots.

Condition and Landscaping: Red Maple is a catch-22 in landscaping: it grows fast, has great color, it can thrive in bad conditions like flooding, droughts, sidewalks, pollution, disease and major damage.... unfortunately they tend to carry these marks and branches can break easily. Many cities use red maple cultivars and hybrids guaranteed to have decent form, it's shallow roots prevent weed (and grass) growth around the trunk. European and west coast cities utilize a hybrid between silver and red maple (Acer x freemanii) as a common hardy street tree. There are two cultivars I will recommend: 'Brandywine' which has dense foliage and 'October Glory' which has deep red fall colors and seeds

Restoration performance: Red Maple makes an excellent forest edge species allowing its vibrant fall color to be fully enjoyed and producing dense foliage to protect the inner woods from drying sunlight (sapling in field above from the Poconos). They're best utilized in wetland restoration projects as they are quite prolific and survive long periods of standing water.

This account is made to post fumos with plants and sometimes others. It's inspired by other accounts. It's not going to be consistent, so click on the blog and follow the archives for hashtags to find specific posts. I also have another account on bluesky. I will post a demonstration of the types of posts you will find in this account. Posts on friday will be tagged with "#floral fumo fridays" while posts that take place any other days, like this one, will be tagged "#floral fumo flutters" I will use other tags relating to touhous and other characters used but it will mostly be Yuuka Kazami from Touhou Project.

photo : ©️skondal The holes in the maple leaves showed that she has fed other little lives, I like it very much! ◠‿◠Thank you! 🙏 ℒan~*

外衣穿洞洞

美麗的通紅

自然是給予

生命如秋楓

─ (五絕) 楓紅 • 仲茵 poem - Maple leaves turn red by Chu Lan

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《Red Maple October Glory》

This wonderful cultivar of the more common red maple; Acer rubrum October Glory is a large, deciduous tree with rather erect main branches. The three-lobed leaves are deep green above, and whitish beneath, and turn bright crimson in autumn. The flowers are crimson and borne on the bare branches. This tree is good in a big architectural garden or in a low-maintenance garden, as it needs minimal pruning, although it can be subject to some pests and diseases. Propagate by grafting.

▪︎Hardiness/ Very hardy.

▪︎Sheltered/the plants need a shady, sheltered spot in the garden.(Full sun or partial shade).

▪︎Soil/ Moist but well-drained, or well-drained, acid to neutral soil.

So long, leaves.

Autumn has fallen.

This specimen of red maple (Acer rubrum) was collected on November 13, 1915 by Otto Jennings near Finleyville, Pennsylvania (about 30 miles south of Pittsburgh).  Jennings was an influential botany curator (and biology professor at University of Pittsburgh and director of Carnegie Museum, among many other roles through his many decades career at the museum).

Just imagine how beautifully red these leaves must have been.   And you’ll have to imagine because this specimen is just twigs!

But upon closer look, the twigs have a lot to admire.  As with other deciduous trees in Pennsylvania, the buds are primed and ready.  In spring (as early as March for red maple!), these buds will swell and flowers will emerge.  Leaves will follow.  

But first, we wait it out through winter.  

Pay attention to tree buds this winter. They have a lot to say.

Find this red maple specimen here (along with 512 others!).

Check back for more! Botanists at the Carnegie Museum of Natural History share digital specimens from the herbarium on dates they were collected. They are in the midst of a three-year project to digitize nearly 190,000 plant specimens collected in the region, making images and other data publicly available online. This effort is part of the Mid-Atlantic Megalopolis Project (mamdigitization.org), a network of thirteen herbaria spanning the densely populated urban corridor from Washington, D.C. to New York City to achieve a greater understanding of our urban areas, including the unique industrial and environmental history of the greater Pittsburgh region. This project is made possible by the National Science Foundation under grant no. 1801022.