American basswood Identification (Tilia americana)

Check the leaves, flowers, and fruit on Tilia americana.

• Leaves are simple and alternate, broadly heart-shaped, with a pointed tip and uneven leaf base.
• Leaf blades are usually 4-6 inches (10-15 cm) long, with coarse serrated edges and long stalks.
• Flowers hang in small clusters from a long, pale, leaf-like bract attached above the cluster.
• Fruits are small, round, and dry, hanging beneath the same strap-like bract.

The long bract attached to flowers or fruit is one of the quickest visual checks.

Tilia americana shows clear visual shifts from sapling form to flowering and fruiting maturity.

• Young plant: Young plants are narrow and upright, with smooth gray stems and large heart-shaped leaves on long stalks; lower branches often persist close to the ground.
• Mature plant: Mature trees develop a broad, rounded crown and a straight trunk with furrowed gray bark; leaves commonly reach 4-8 inches (10-20 cm) long.
• Flowering stage: At flowering, pale yellowish clusters hang beneath a long, leaflike bract, making the canopy look pendant in ways not seen on nonflowering plants.
• Fruiting stage: After flowering, the same drooping clusters carry small round nutlets beneath the persistent bract, adding distinct beadlike structures among the leaves.

A few selections of American basswood are identifiable at a glance by crown shape or leaf color.

• Tilia americana 'Redmond': Typically forms a strong pyramidal crown, narrower and more upright than the broad, rounded outline of the species.
• Tilia americana 'Nova': Shows a dense, symmetrical oval to pyramidal canopy with a more uniformly upright habit than the typical spreading crown.
• Tilia americana 'Legend': Usually has a straighter trunk and a more narrowly oval crown, giving a tidier outline than the species.
• Tilia americana 'DuFast': Recognized by its distinctly narrow, columnar habit, with a much tighter spread than typical trees.
• Tilia americana 'Aurea': Separated by yellow to golden new foliage, rather than the usual medium green leaves.

In spring, American basswood leafs out with large, soft green, heart-shaped leaves. In early summer, dangling clusters of small pale yellow flowers appear beneath a long, narrow, leaf-like bract, a strong field mark when the tree is in bloom. By fall, the foliage turns yellow before dropping. After leaf fall, the broad crown, gray furrowed bark on older trees, and reddish winter buds are easier to see.

Several linden relatives can be mistaken for Tilia americana at a glance.

Tilia americana is native to eastern and central North America, from southern Canada south into the northeastern and midwestern United States. It is most often found in rich deciduous woods, stream valleys, and moist slopes. Seeing a large linden in mesic forest, rather than dry upland or coastal habitat, helps narrow identification toward this species.