Plant lovers will forever be saying they have a new favorite plant. I seem to collect a new love each week, either through field observation or by reading a new attribute or historical use. Tilia americana has been an intrigue of mine ever since I learned the leaves were edible. Just the name alone, Tilia, is beautiful. If I had a daughter I would totally name her Tilia (or Mertensia, but I digress).
Earlier this Spring, while working in the nursery, I impulsively changed gears to separate and save a cluster of young Basswoods once heeled in temporarily, and now thrice forgotten. They were crammed between gooseberry and a fellow misfit tree, a sweet Cherry also heeled in prior, but was too far on their way to being a full size tree to transplant elsewhere. These Basswoods had put on a lot of growth despite being neglected and stuck in their pots for a few seasons. As I was digging them out, cutting the roots which escaped their pots in attempts to establish permanency, I took a break to sample the leaves which I recall Samuel Thayer mentioning were what he uses most in his raw, wild salads. Maybe it was partly shock and partly novelty, but I found the newly formed leaves to be quite delectable! I fell in love with this tree and planted one immediately in my already over-planted (with woodies) homestead.
I was curious why a tree which grows 100’ high would have such tasty leaves. It just seemed intuitive to me that such a tree would be one that could be cut low and grown as a shrub in which to produce more edible leaves at a height suitable for picking. I almost sawed my newly planted Tilia to the ground right then and there, but decided to double check this instinct. The book, Edible Forest Gardens gave confirmation- Basswood is an excellent coppice species. They also grow fast, so they seems to be a likely candidate for silvopasture systems and land restoration work.
The best time to harvest the leaves for human palatability is when they are young, shiny, just unfurling from their buds. The older the leaves are the more tough and mucilaginous they get. They can be eaten raw or cooked in any stage.
The leaves are just one component to the human value of basswood. The mucilaginous properties of the plant make the freshly opened flowers soothing as a tea to drink when dealing with a cold and fever. Linden flowers, a well known tea herb, are usually from the European cousin to Basswood, Tilia cordata, but it seems the flowers of T. americana are used similarly. It is recommended to harvest these flowers when they are freshly opened, not once they have aged, because it is claimed they become a narcotic. But the freshly opened flowers can be used fresh or dried for later use. They have a pleasant fragrance, calming to the mind and digestive system, also used for hypertension. The inner bark is soothing to the skin and has been applied to burns.
I’d love to see (or taste, rather) the value added products folks create as they delve deeper into the edible possibilities T. americana has to offer. It is claimed that a chocolate substitute can be made from ground fruits and flowers. The sap can also be used like maple and birch, concentrated into a sweetener or drank as a nourishing refreshment.
As well as providing shade, carbon sequestration, soil stability, water retention and water quality, food and shelter for wildlife, and all the other things trees provide, our native Tilia supports over 130 species of caterpillars! That's a lot of butterflies, moths, and food for birds!
(Bract of likely T. cordata)
The easiest way to identify basswood trees is by the distinct heart shaped leaves or the bract leaf attached to the flower/seed. This leaf looks kind of like a tongue. T. americana is the only North American tree species to have this tongue-like bract. Basswood is tolerant of a range of soils but I see them mostly in moist, lowland woods.
Sources:
Thayer, Samuel. The Forager’s Harvest. Forager’s Harvest Press, 2006.
Jacke, D. and Toensmeier, E. Edible Forest Gardens, Vol II. Chelsea Green Publishing, 2005.
http://www.pfaf.org/ (medicinal and edible uses of T. americana)