Linden

About Linden

Lindens are big, dense shade trees with heart-shaped leaves and dangling clusters of very fragrant, creamy flowers in early summer that bees love, which is why basswood is also called bee tree. American basswood is native from southern Quebec to Manitoba and eastern North Dakota, south to western North Carolina, Tennessee, Louisiana and eastern Texas (wildflower.org); littleleaf linden comes from Europe and is a common, tidy street tree (Morton Arboretum). Japanese beetles love linden leaves, and NC State warns heavy attacks have destroyed mature littleleaf lindens.

American linden is hardy in zones 3-8 and littleleaf linden in zones 3-7 (NC State).

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Plant container or balled-and-burlapped trees; container trees can go in any time the ground can be worked, but fall is best in the South because roots keep growing through mild winters (Clemson). Dig no deeper than the root ball and at least twice as wide, set the top roots level with the soil, and mulch 2-4 inches deep without touching the trunk (Clemson). Lindens transplant easily (NC State, Morton Arboretum). Water young littleleaf lindens in dry spells, and a mulch layer keeps the roots cool (NC State, Morton Arboretum). American linden is easily damaged by ice storms (Morton Arboretum).

Soil

Fertile, moist, well-drained loam; American linden takes clay and dry, rocky soil, and littleleaf linden tolerates alkaline soil but not wet ground, severe drought or salt (NC State, Morton Arboretum).

Test the soil first. Loosen a wide planting area and mix 10-20 percent compost into the native soil you dig out; use only composted material, and don't dig deeper than the root ball (Clemson).

Feeding

• Spring to early summer, after the tree is established, and only if a soil test or weak growth shows a need: slow-release nitrogen fertilizer with a ratio near 3-1-1 or 3-1-2 (3-0-1 or 3-0-2 if the soil test shows enough phosphorus). Spread it evenly from just outside the trunk flare to the drip line and water it in. Clemson cites 2-4 lb of slow-release nitrogen per 1,000 sq ft per year, split between spring and late summer; follow your soil test.
• Late summer to early fall, the second half of the split feeding (only if a soil test calls for it): slow-release nitrogen fertilizer, same as spring. Water it in, and skip it if the tree is drought-stressed, since roots can't take up fertilizer from dry soil (Clemson).

First-year watering matters far more than fertilizer: water daily for the first 2 weeks, every 2-3 days through week 12, then weekly, using 1-1.5 gallons per inch of trunk diameter, until the tree is established (about 1.5 years for a 1-inch trunk). Skip a watering only after more than an inch of rain (UMN). Lindens are sensitive to heat and soil compaction; water young trees in dry spells and keep a mulch layer over the roots (NC State, Morton Arboretum). Too much fertilizer can burn roots and push soft growth (Clemson).

Harvest

Blooms in early summer, June to early July, in hanging clusters on a long, strap-like bract; the pea-sized nutlets follow in late summer (NC State, Morton Arboretum). Littleleaf linden takes heavy pruning and can even be clipped into a hedge (NC State).

Varieties (13)

NC State and the Morton Arboretum document these 13 cultivars, chosen mainly for shape and size.

Pests to watch for

Japanese beetle, Aphids, Lace bugs (azalea and chrysanthemum lace bugs), Scale insects, Twospotted spider mite

Diseases and problems

Verticillium wilt, Anthracnose, Powdery mildew, Leaf spots, Canker

In the kitchen

NC State lists the dried flowers for tea, young leaves for salads and the sap for syrup, but warns that overusing the dried-flower tea can damage the heart.

Safety: NC State gives no poison rating, but warns that overusing linden-flower tea can cause heart damage.

Pets: Non-toxic to dogs, cats and horses (ASPCA, Linden, Tilia americana).