Tree of the Week: Basswood (Tilia caroliniana)

It's the end of June. We had a couple of rainy days this past month, which were a real treasure. However, for the past several days it has been blue skies, blindingly bright sunshine, and sweltering heat. We need some shade to block out that summer sun.

Basswood (Tilia caroliniana) is a lesser-known native that makes for a great shade tree. It needs more water than some trees, but it grows fast and provides a lot of cover. The basswood pictured below shades one of our main thoroughfares. This individual was collected in the spring of 1994, from the Walter Jacobs Nature Park, located here in Caddo Parish. At more than twenty years of age, this basswood provides a bounty of shade.

This is a low, shady spot in the arboretum. Several trees are making this a cool retreat. The photographer is standing in the shade of a flowering magnolia, a sweetgum, and a swamp white oak. The basswood is pictured to the right of the white bridge. It's growing next to the arboretum drainage channel.

In this photo, the thick basswood trunk is pictured immediately to the left of the white bridge. The view of the basswood is obstructed by the very healthy grouping of Hercules'-club.

The basswood is growing next to the sidewalk, which results in excellent shade for those passing through the arboretum. But some light still gets through, as we see dappled sunlight on the trunk.

The trunk is divided near the base of the tree, giving this basswood an interesting form.

The trunk divides into two unequal branches.

The bark shows division as well. Smooth, light-gray bark is juxtaposed with rough, dark-gray bark.

The trunk and branches mostly have smooth gray bark.

Patches of deeply grooved, dark-gray bark are found near the base of the tree, particularly above the division in the trunk.

Following the trunk upwards we mostly see smooth gray bark surrounded by light branches and innumerable leaves, providing all that good shade.

A few immature fruits can be found hidden among the leaves.

Basswood leaves alternate along the branch.

On this twig we see large, rounded leaves and long, yellow-green bracts. The immature spherical fruits are attached to stalks that emerge from the bracts.

The upper surface of the basswood leaf is dark green and smooth. Leaf and stalk together measure under 6 inches in length.

Underneath, the basswood leaf is light-green and smooth (hairless). Note the asymmetrical shape and uneven base. Leaf margins are toothed.

Leaf, bract, stalk, and immature fruit

The flower/fruit stalk emerges from the bract.

Basswood fruits are small and inconspicuous, measuring approximately a quarter of an inch.

Last June, the basswood flowers were featured in a 'What's in Bloom?' post. You can see a picture of the tiny, fragrant flowers here.

For more information about this species consult the following sources:
Texas A&M (Forest Service)
Texas A&M University (Aggie Horticulture)
United States Department of Agriculture (zoom-in on distribution map)