Most often seen at 40 to 50 feet in height with a spread of 35 to 40 feet, American linden or basswood is capable of reaching 80 to 100 feet or more. The tree is pyramidal when young but develops into a striking specimen with an upright, oval canopy atop a tall, straight trunk. The lower branches remain on the tree and gently drape toward the ground before sweeping up in a gentle curve. The four to eight-inch-long, heart-shaped leaves are dark green throughout the year fading only to pale green or yellow before dropping in autumn. In June, the trees produce abundant, two to three-inch-wide clusters of very fragrant, light yellow blooms which are extremely attractive to bees, who make a delicious honey from their harvests. The small, grey nut which is later produced will persist on the tree until midwinter. The trunk can grow to six feet or more across on mature specimens.
Figure 1. Mature Tilia americana: American linden Credit: Ed Gilman, UF/IFAS
General Information
Scientific name: Tilia americana
Pronunciation: TILL-ee-uh uh-mair-ih-KAY-nuh
Common name(s): American linden, basswood, American basswood
Family: Tiliaceae
USDA hardiness zones: 3A through 8B (Fig. 2)
Origin: native to North America
Invasive potential: little invasive potential
Uses: hedge; specimen; shade; street without sidewalk; tree lawn > 6 ft wide
Availability: not native to North America
Figure 2. Range
Description
Height: 50 to 80 feet
Spread: 35 to 50 feet
Crown uniformity: symmetrical
Crown shape: pyramidal, oval
Crown density: dense
Growth rate: moderate
Texture: coarse
Foliage
Leaf arrangement: alternate (Fig. 3)
Leaf type: simple
Leaf margin: serrate
Leaf shape: ovate, cordate
Leaf venation: pinnate
Leaf type and persistence: deciduous
Leaf blade length: 4 to 8 inches
Leaf color: green
Fall color: yellow
Fall characteristic: not showy
Figure 3. Foliage
Flower
Flower color: yellow, green
Flower characteristics: showy
Fruit
Fruit shape: round, oval
Fruit length: less than .5 inch
Fruit covering: dry or hard
Fruit color: tan
Fruit characteristics: does not attract wildlife; not showy; fruit/leaves not a litter problem
Figure 4. Fruit
Trunk and Branches
Trunk/bark/branches: branches droop; not showy; typically one trunk; thorns
Pruning requirement: needed for strong structure
Breakage: susceptible to breakage
Current year twig color: green, brown
Current year twig thickness: medium
Wood specific gravity: 0.37
Culture
Light requirement: full sun, partial sun, or partial shade
This tree is large and needs plenty of room to develop. Branches should be well-spaced along a central trunk to allow for development of a durable structure. Left unpruned, weak crotches with embedded bark can develop but the wood is flexible so branches usually do not break from the tree. Be sure main branches remain less than about half the diameter of the trunk. Plant it as a specimen or shade tree on a commercial property where there is plenty of soil space available for root expansion. Be prepared to remove sprouts periodically from the base of the trunk.
A North American native tree, American Linden prefers moist, fertile soils, acid or slightly alkaline, in full sun or partial shade. It is more shade-tolerant than many other large trees. The leaves will show appreciable browning and scorching after a particularly dry season, but the tree appears fine the following year. It is often found growing along moist stream banks but tolerates some drought. Best located in moist sites.
The cultivar 'Redmond' grows 65 to 75 feet tall and has a pyramidal shape with upright branches and shiny leaves, drought-tolerant; 'Fastigiata' is narrowly pyramidal with fragrant yellow flowers; 'Legend' is resistant to leaf rust, pyramidal, grows with a single, straight trunk, and upright, well-spaced branches. These can all be used in large tree lawns along streets.
Many taxonimists lump Tilia carolinana, Tilia heterophylla, Tilia floridana, and Tilia georgiana together with Tilia americana.
Propagation is by seed, cuttings, or grafting.
Pests
Mainly aphids, although Japanese beetle, European linden bark borer, linden borer, walnut lace bug, caterpillars, basswood leaf miner, elm sawfly, scales and Linden mite can all be troublesome problems. The aphids will secrete a honeydew which will result in a dark soot over objects below the tree, such as parked cars or lawn furniture.
Diseases
Anthracnose, leaf blight, canker, leaf spots, powdery mildew, and verticillium wilt are some diseases than can infect American linden. Leaf rust can cause some defoliation.
