Last updated: October 28, 2026
Article
American Basswood
About American Basswood (Tilia americana)
American Basswood, also known as American Linden, is a large deciduous tree (a tree that sheds its leaves annually) native to eastern North America. It is common throughout the Northeast and grows best in moist, well-drained soil, though it can tolerate a range of conditions. In urban environments, it may be less tolerant of heat stress and air pollution compared to some other shade trees.
Within the park, basswood serves as both a canopy tree and a valuable wildlife resource. Its large leaves create cool, shaded conditions beneath the canopy. Its flowers, fruits, and foliage provide food and habitat for numerous insects, birds, and mammals throughout the growing season.
Commonly known as the bee tree, basswood’s nectar-rich flowers are famous among beekeepers and naturalists. During flowering season, the tree can seem to hum with activity as native bees, honeybees, flies, beetles, and other pollinators visit the blossoms.
People have long valued basswood for its lightweight wood, using it for woodworking, musical instruments, and carving. The strong fibers of its inner bark, known as bast, were traditionally used by Indigenous peoples and early settlers to make rope, mats, baskets, and other woven materials. These uses of bast gave rise to the tree’s common name “basswood.”
Identification
American Basswood is easiest to recognize by its large, heart-shaped leaves. The leaves are typically four to eight inches long, with finely toothed edges and a pointed tip. One of the best identification clues is the uneven, lopsided lead base, where one side of the leaf attaches to the petiole (the stalk that joins a leaf to a stem) slightly lower than the other.
Leaves are arranged alternately along the branches and are dark green with a pale underside. Small tufts of rusty-brown hair are often visible where the veins meet on the underside of the leaf.
Mature trees develop dark gray bark with long, narrow ridges and deep furrows. Young trees have smoother bark that becomes increasingly rough with age.
In early summer, look for clusters of fragrant pale-yellow flowers hanging beneath a distinctive pale-green bract (a modified leaf or scale, typically small, with a flower or flower cluster in its axil). Later in the season, round fruits develop beneath the bract and remain attached until they fall together in autumn.
Phenology Highlights
Phenology is the study of recurring seasonal events in plants and animals. The following phenophases, distinct and observable stages in the annual life cycle of a plant or animal, are monitored as part of the National Parks of Boston Tree Monitoring Program.
Breaking Leaf Buds
Plant Image Library CC-BY-SA 2.0
American Basswood leaf buds can range from lighter to darker red and are relatively smooth. In spring, the buds swell and unfold into soft, light-green leaves. New leaves often emerge folded and slightly fuzzy before rapidly expanding.
Leaves & Early Season Leaf Expansion
Flickr user via NP Gallery. Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic (CC BY-NC-SA 2.0): https://creativecommons.org/licenses/by-nc-sa/2.0/
American Basswood has simple, heart-shaped leaves that are among the largest leaves of northeastern forest trees. The leaves have finely serrated margins, prominent pinnate venation, and an alternate arrangement along the twigs. Basswood leaves expand quickly in late spring. Young leaves are pale green and soft-textured before maturing into large, dark-green leaves that create a dense, shady canopy.
Colored Leaves & Falling Leaves
Katja Schulz via Wikimedia Commons CC BY-2.0
Fall color is typically a clear yellow to yellow-green. Basswood leaves usually do not develop the orange or red colors as seen in maple species, dropping relatively quickly after turning yellow in autumn.
Flowers or Flower Buds & Open Flowers
Plant Image Library via Wikimedia Commons CC BY-SA 2.0
American Basswood typically flowers from late June into July in New England. Clusters of fragrant, pale-yellow flowers hang from a distinctive strap-like green bract. The flowers are highly attractive to bees and other pollinators, often filling the surrounding area with a sweet fragrance.
Flowers are considered open when the cream-colored petals have spread and the stamens and pistils are visible. Flower clusters often attract numerous bees, flies, and other insect visitors. The open flowering phase typically ends when the flowers’ reproductive structures have dried or wilted, signaling that the flowers are spent.
Basswood flowers release pollen shortly after opening. Pollen-bearing stamens (the male fertilizing organs of a flower) become prominent as flowers mature, and insect activity around flowering clusters is often especially noticeable during this period.
Fruits
NPS / W. Kaselow
Following pollination, round, pea-sized fruits develop beneath the persistent bract. The fruits remain attached in hanging clusters throughout much of the summer.
Ripe Fruits & Recent Fruit or Seed Drop
Steve Baskauf. Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic (CC BY-NC-SA 2.0): https://creativecommons.org/licenses/by-nc-sa/2.0/
Fruits change from green to grayish-brown as they mature, usually from late summer into early fall. The fruit wall becomes dry and firm when ripe.
In autumn, fruit clusters fall with their attached bracts. The leaf-like bract acts as a wing, helping wind carry seeds away from the parent tree. Look for fallen fruit-and-bract clusters beneath the canopy.
Learn More
- Tilia americana (American linden): Go Botany. (n.d.). Native Plant Trust: Go Botany. Retrieved September 4, 2026.
- Tilia americana - Plant Finder. (n.d.). Missouri Botanical Garden. Retrieved September 4, 2026.
- Tilia americana (American Basswood, American Linden, Basswood, Bee Tree, Carolina Basswood, Lime Tree, Linden, White Wood) | North Carolina Extension Gardener Plant Toolbox. (n.d.). North Carolina Extension Gardener Plant Toolbox, NC State Extension. Retrieved September 4, 2026.
- American Basswood (Tilia Americana): Types, Leaves, Bark (Pictures). (2021, April 21). Leafy Place.
- The Editors of Encyclopedia Britannica. (2017). Bast fiber. In Encyclopædia Britannica.
National Parks of Boston Tree Monitoring Program
By observing seasonal changes in trees, volunteers help scientists better understand how plants respond to changing environmental conditions over time.