Plant Growing Post: Lupinus perennis sub. perennis
Hello everyone, with February coming around it's a great time to start thinking of growing. If you're like me and are into experimentation and love threatened species, consider growing the Northeast's only native lupine: the Sundial/Wild Lupine
Why is it important to grow this species? 1. It is the larval host plant for the Federally listed Karner Blue butterfly whose range once spread from parts of Wisconsin to Maine but is now restricted to very localized areas of Wisconsin, Michigan, and New York State. (Species survival is complicated due to restricted mobility and climate change). 2. The plant itself has also become incredibly rare in NJ, New York, and Pennsylvania due to land use changes and lack of natural fire regimes.
Why am I doing this? To hopefully teach people closer to existing Karner Blue (image above from inaturalist) populations with successful grow methods. Reddit guides were so snarky and rude I wanted to make a nicer guide. Also, personally, in NJ there are only 4 known populations of this lupine, historic populations were once more plentiful, and the Karner Blue may have existed here as well.
The natural habitat of Sundial/Wild Lupine is Oak-Savannah, these aren't necessarily rare but they're more common in acidic mountain tops and sandy barrens. The key growth factor needed for our native lupine is open canopy with enough sun to remain successful. I'm letting you know the native habitat to key you in on its tougher-to-grow features: infertile soils and a DEEP taproot.
Okay let's begin: I'm always a proponent of collecting wild local seed from native populations, unfortunately, local populations were on private land so I settled for a trusted seller who does genetic testing: Prairiemoon (ignore the Carex) but there are other local sellers in New England. Genetic testing is important because some nurseries will sell you hybrids which are not helpful to the Karner Blue and potentially invasive. I have grown wild lupine before but my dogs killed them so this was a new attempt.
Wild collected seeds require moist cold stratification for 60-90 days, though some will germinate with no stratification and my most successful germination came from scarification and quick stratification (the sellers germination process essentially). For this you want to place the seeds in between a sheet of sand paper and rub until the outer shell is nicked enough to allow water to penetrate.
Here is where inoculation comes in: members of fabaceae have a relationship with a bacteria which allows the roots to capture nitrogen from the air. Some places sell the specific inoculation but the bacteria is present in most soils. This is rather taboo on my end but for species like this I usually take some soil near an existing legumous species (where this bacteria is basically guranteed to be present) mix it with water and take a light amount of this water where I'll briefly soak the seeds in a shallow dish before stratification. This is optional but I've done this for years and have noticed better growth in my Fabaceae than those I haven't preformed this on. If you include too much silt in your liquid you will introduce harmful bacteria as well. Also, it's possible I'm not really doing much with this but better growers than I will correct me.
Finally cold stratification: place the seeds flat in a moist (not soaking wet) paper towel then place in a bag in the fridge for a minimum of 10 days. Once the seeds swell in size they're ready to plant (Day 0). Don't be like me and do this wayyyyyy too early by mistake.
I started my seedlings in a seed starting tray with peat to ensure germination, by [Day 5] they should begin to sprout. On [Day 9] the first leaves form and the taproot develops, you NEED to move them to a deeper pot quickly or else the taproot will be damaged. I got cloth deep root (10") pots and filled them with an infertile mixture (remember they derive nitrogen from the atmosphere) of peat and sand... you don't have to use peat, you can mix soil I just had a lot of peat left over. If you transfer everything correctly and not over water, the taproot will happily continue to develop as true leaves begin to form [Day 16 and 18 below]
I personally sit my plants on a south facing window and then give an additional 3 hours of LED lights after sunset. I've given them around 6-8 hours of direct light but I'm probably spoiling these plants because I'm growing them with my orchids. If you do this 10 days before last frost, you can leave it outside. I currently have 12 Lupines: starting at 90% seed viability, 18 seedlings (only tranferred 14), only two seedlings died after the first 15 days
Continued development: [Day 26] image below left- second leafing. [Day 29 Image 1] continued growth. Last image [Day 38] with third leafing. When it's time to plant out I recommend making sure you dig a hole as deep as the taproot and plant in full sun in dry soil.
I do not believe these make flower in the first year, like many lupines they go dormant in summer, this batch's survival is questionable because it's February. I'll keep everyone updated!
