Tilia americana (American Basswood)
Also known as: | American Linden, Basswood |
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Genus: | Tilia |
Family: | Malvaceae (Mallow) |
Life cycle: | perennial woody |
Origin: | native |
Habitat: | part shade, sun; average moisture; deciduous forests, woodland/field edges, urban landscapes |
Bloom season: | June - August |
Plant height: | 60 to 110 feet |
Wetland Indicator Status: | GP: FACU MW: FACU NCNE: FACU |
MN county distribution (click map to enlarge): | |
National distribution (click map to enlarge): |
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Detailed Information
Flower:
Hanging, branching cluster of 6 to 18 pale yellow flowers suspended from a leaf-like bract that forms in leaf axils on this year's new growth, emerging after the leaves in late spring. The leafy bract is pale yellow-green, 2 to 4 inches long, oblong-elliptic to spatula-shaped, rounded at the tip, rounded at the base, on a naked stalk or tapered to a winged stalk. The flower cluster's stalk (peduncle) is fused (adnate) on the lower half of the bract, the stalk's free portion 1½ to 2 inches long before branching into flower stems.
Flowers are ¼ to 1/3 inch across with 5 petals and 5 sepals, both spreading to ascending, the sepals boat-shaped, pale yellow to nearly white, the petals somewhat longer, more yellow especially with age, more oblong-elliptic, also boat-shaped but somewhat flatter. In the center are numerous stamens, up to 60, shorter than to about as long as the petals, in five groups around the central pistil. The innermost stamen of each group is typically modified into a petal-like staminode (sterile stamen), layered just in front of the petal. A single straight white style, longer than the petals, sits at the tip of the pale green ovary, the tip of the style with 5 tiny lobes.
Leaves and bark:
Leaves are simple, alternate, 4 to 6 inches long and about as wide, broadly egg-shaped to nearly round, the tip abruptly tapered to a sharp point, the base asymmetrical and heart-shaped or one side more angled or straight across. Edges are finely toothed. The upper surface is hairless and deep green, the lower surface pale green and hairless except for tufts of short, woolly hairs in at least some vein axils. Fall color is deep yellow with hints of orange, the edges often browning prior to leaf drop.
Young twigs and branches are slender and limber, smooth with scattered lenticels (pores), the young bark silvery gray-brown. Buds are oval to nearly round, rounded to short point at tip, typically reddish brown.
Bark is stringy, smooth and gray on branches, developing ridges and furrows on larger branches and the trunk. Trunks on larger Minnesota specimens can reach 2 to 3 feet diameter at breast height (dbh), though some eastern US specimens can reach over 5 feet. Clumps of multiple trunks from basal sprouts are common, cut stumps frequently sending up multiple stems.
Fruit:
Fruit is a round, woody nut-like berry, ¼ to 1/3 inch diameter, covered in minutes hairs and maturing from green to light gray-brown.
Notes:
American Basswood (a.k.a. American Linden) is a large forest tree found throughout most of Minnesota's rich forest areas, though most predominant in central and south eastern woodlands, and is an important member of the Maple-Basswood forests of the area. In the open it reproduces a large, dense crown, typically somewhat columnar to vaguely pyramidal. The flowers are fragrant and copious, pollinated by bees and providing for a large honey crop. The abundant seeds are an important food source for a wide range of small mammals and birds, even foxes. The bark is eaten by porcupines and squirrels, the latter sometimes stripping the stringy bark for nest construction. Deer browse heavily on young shoots, leaves and winter twigs.
American Basswood is only occasionally planted as a landscape tree. The wild form has generally been considered messy and weak wooded with a rank growth form. It is prone to heavy basal suckering (a major way it regenerates in the wild) and wind throw. There are however, now a number of horticultural cultivars available that have been selected for narrower columnar or pyramidal forms. The similar European Little-leaf Linden (Tilia cordata) is heavily planted in urban landscapes. It differs in several floral characteristics but over all it is a smaller tree with smaller leaves (2 to 4 inches long) and has been heavily selected for more tightly pyramidal forms. The native Linden is also host to a native wood boring beetle (Linden borer) and while it generally tolerates the pest quite well—its rapid growth usually out growing any injury—young trees under stress in urban environments can be seriously damaged by it.
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More photos
- American Basswood tree
- American Basswood tree
- fall color
- flowering branches
- seedling
- multiple stems from basal sprouts
- leaf scan
- tufts of hairs in leaf vein axils
- comparison of Tilia americana and T. cordata twigs
Photos by K. Chayka taken in Ramsey County. Photos by Peter M. Dziuk taken in Hennepin, Kanabec and Ramsey counties.
Comments
Have you seen this plant in Minnesota, or have any other comments about it?
on: 2020-06-17 21:28:13
This summer I have noticed that many of the linden trees that are in my neighborhood (Bryn Mawr in Minneapolis) and also in Theodore Wirth Park are not flowering. What could have caused this? I haven't ever noticed a year where they weren't all covered with flowers, but some don't even have the paddle or buds for the blossoms. Could they be affected by a disease?
on: 2020-07-05 09:38:52
Absolutely adore this tree. So majestic. We have several on our wooded property.
on: 2020-12-16 21:59:04
In Alimagnet Park in Apple Valley, there are only a few of these trees around. I find them more attractive than the small pyramidal landscaping forms, but both are heavily feed upon by Japanese beetles, which can strip most of the leaves off by late summer. Unlike most trees around here, it has smoother, light-colored bark, medium to large-sized, rounded leaves. It is damaged by deer when bucks use it to scrape their antlers.
on: 2022-05-21 00:48:24
We have a number of these in the woods behind our house. It's mostly old white and red oaks out there, with the occasional big elm, or black cherry/aspen clump, but there are some massive basswoods towering over everything else (even the cottonwoods, which are utterly ginormous). There is also quite a few seedlings of various ages scattered around the forest floor. They're beautiful trees.
on: 2022-06-01 18:59:17
There are two lovely basswood trees by the front entrance (facing West) of Good Counsel Provincial House. The stipules are just beginning to show sprouts of fruit.
on: 2023-07-23 12:58:01
Volunteered in a spot that's under both an elm and a roof overhang. Loam soil, decent moisture, maybe 2 hours of full sun per day. My guess is that the squirrels planted it.
on: 2024-06-26 22:51:01
I see these planted as landscape trees quite a bit throughout Minneapolis. Around both Seward co-op's and powderhorn park to name a couple spots. I've noticed the flowers are more succulent and don't smell quite as good.