One of our venerable native deciduous trees in the Wildflower Garden is the American Basswood (Tilia americana) - a member of the Basswood, or Linden Family (Tiliaceae). The species is indigenous to the Garden and Curator Susan Wilkins has planted some new ones in recent years. Eloise Butler wrote of “a goodly sized basswood in the east meadow and young basswoods are springing up on every side.” (1)
It is a long-lived species, growing to 60 to 100 feet in height with leaves so soft certain Boy Scouts I know call it ‘nature’s toilet paper.’ The flowers are bisexual so you only need one tree to produce fruit - and fruit and flowers is one of the things I want to talk about.
Flowers mature to a 1/4 inch round hard nutlet that usually contains just one seed. The fragrant flowers have been used to make a soft flavorful tea and from the nectar bees produce the palest and most complex honey, with floral scents and notes of mint. It is not uncommon to find honey in your neighborhood grocery labeled “Basswood”.
The next interesting use of the tree requires some industry. It was discovered by a French chemist, whose full name, sadly, seems to have been lost and who is known only as “Missa”, that the flowers and nutlets of the Linden family make a great chocolate substitute. First you collect the fragrant flowers and dry them, and then collect the round nutlets which form from the flowers that you left on the tree - and collect them before they mature. By proper mashing and the addition of little grape seed oil, you will have a fine chocolate, equaling that produced from cacao beans and with a superior aroma. You will find various recipes on the internet.
Many attempts were made in Europe, back as far as Frederick the Great, to make a commercial success of it but no one could ever solve the problem of ‘shelf-life’. If you don’t use it right away, some may keep in cold storage for a few days, but that’s it, then the paste denatures and the aroma and taste is gone. The French botanist Étienne Pierre Ventenat (1757-1808) suggested that the fruits of the American Lindens may have produced a greater success, but while they may make a better product the shelf-life problem remains. So, back to cacao beans - or you could try the roots of Purple Avens or the nuts of Chinquapin Oak, but the results from those two plants never came close to the Lindens. (2)
A more practical use of Basswood by our Native peoples was to make twine from the bark fibers. Frances Densmore’s extensive study in the 1920s of plant use by the Minnesota Chippewa, particularly the White Earth group, detailed medicinal, food and craft uses of various plants. Twine is a multi-purpose article and it was made in this manner: Bark was cut from the Basswood tree in long strips and soaked in the lake water for several days. Then the soft useful inner bark could be separated from the tough outer bark into strips less than an inch wide and stored in coils for future use. The strip could be used full width if toughness and strength was needed, or separated into fine threads as soft and fine as cotton. When twine was needed, the fibers could be twisted to make twine.
The two historical photos below show the large strips being removed from the water and then the inner basswood fiber being stored in coils. Photos ©Smithsonian Institution.
Basswood is found in most counties of Minnesota except for many in SW section - the old prairie area. It is the only species of Tilia native to the State. Every woodlot should have one or two, if only to keep the bees busy.
(1) Annals of the Wildlife Reserve, 1926, unpublished.
(2) Fernald, Merritt L. & Alfred C. Kinsey– Edible Wild Plants of Eastern North America– Harper & Row– 1958
(3) Densmore, Frances– How Indians Use Wild Plants for Food, Medicine & Crafts, 1973. (Note: The contents of this book were originally published in the Forty-fourth Annual Report of the Bureau of American Ethnology to the Secretary of the Smithsonian Institution, 1926-1927).