Tree · Malvaceae
American Basswood
Tilia americana
A generous shade tree that gives a garden fragrant summer flowers and a settled sense of place.
Full sun
Every 7–14 days
USDA 3–8
60–80 ft · 18.3–24.4 m
Overview
American basswood, the tree most gardeners know as linden, is the sort of native shade tree that anchors a property and gives a place its character. Through late spring and early summer it opens small, pale-yellow flowers whose fragrance drifts across the yard and keeps the pollinators busy, which is how it earned the affectionate name bee tree. Left to mature, it rises to a commanding 60 to 80 feet (18 to 24 m) with a broad, rounded crown that reshapes the skyline of a garden.
It is a tree for people who plant with the long view, and one that asks little in return. It stands up to hard winters, works in full sun or part shade, and takes ordinary soil in stride as long as it drains. The broad crown lays down a deep, welcoming shade that turns a lawn into a place to sit, and the soft, light wood is the one that gave basswood its old standing among carvers.
Give it a spot with room to grow and it becomes the easy centerpiece of an outdoor room. The one detail to plan around is that aphids favor it and drip sticky honeydew through summer, so it pays to think twice before you set a dining patio or a parking spot directly beneath the canopy.
Care
The short version: site it in full sun to part shade in moist, well-drained soil, keep the water steady through its early years, and let it settle into the garden with little fuss.
Light
Linden looks its best in full sun, where the crown fills in and the bloom comes on strongest, and it takes partial shade in stride. A shadier corner still yields a healthy tree, if a looser and more open one.
Water
Keep a young tree evenly moist, watering every 7 to 14 days through dry stretches while it finds its feet. Once settled it handles some drought, though it always shows better for steady moisture, so spare it the long dry spells.
Soil
It asks little of the ground and takes clay, loam, or sand, provided the soil stays medium-moisture and well-drained. Any pH from 5.5 to 8.0 suits it, which covers nearly every garden bed you are likely to have.
Temperature
This is a cold-hardy tree, at ease anywhere from -40°F to 100°F (-40°C to 38°C). It carries harsh winters and hot summers alike, which is why it settles happily into gardens across so much of the country.
Humidity
Outdoor humidity is never a concern for a linden, so there is no figure to meet. Air movement counts for more, since still, damp air pooling around the canopy is what invites the leaf spots and mites.
Feeding
A settled tree in decent soil rarely calls for feeding at all. If growth looks thin, work a balanced slow-release tree fertilizer into the soil in early spring, but keep it light, since too much nitrogen only feeds the aphids.
Pruning
Prune in late winter to early spring to shape a single strong central leader and to lift out dead, damaged, or crossing branches. The tree also sends up basal suckers and sprouts, so clear those away as they appear.
Repotting
Linden belongs in the landscape rather than a container, so repotting drops away once it is in the ground. If a nursery tree shows roots circling the pot or slipping out the drainage holes, get it planted out before the roots girdle.
Size & spacing
Give a linden real space, since it reaches 60 to 80 feet (18 to 24 m) tall and spreads 30 to 60 feet (9 to 18 m) wide. Place it well clear of buildings, walls, and overhead lines so the broad crown can fill out and frame the garden as intended.
When to plant
Linden is a tree, so it keeps no annual sowing calendar to work around. Plant young trees in spring or fall, once the hard frosts have passed, and the fragrant flowers arrive on cue from late spring into midsummer to mark the season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall, after the threat of hard frost has passed
- Harvest: Fragrant pale-yellow flowers in late spring to early summer (May to July)
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
A healthy linden largely looks after itself, and most of what shows up in the canopy is cosmetic rather than cause for concern. Match the signs below before reaching for any treatment, since a mature tree carries pest pressure that would unsettle a smaller planting.
Wilting limbs with sawdust and round holes low on the trunk
The linden borer works within the wood of the lower trunk and limbs, and the round exit holes and sawdust-like frass at the base are the giveaway. Prune out and dispose of any infested limb. Because borers favor stressed trees, the surest safeguard is a well-watered specimen with bark spared from mower and trimmer nicks, and a trunk infestation is one to hand to an arborist.
Fix:
- Prune out and destroy borer-infested limbs
- Keep the tree vigorous, as borers preferentially attack stressed trees
- Consult an extension office or arborist for severe trunk infestations
A sticky sheen on the leaves and a dark cast on the ground beneath
That glossy stickiness is aphid honeydew, and the darkening that follows is nothing more than a harmless sooty mold living on the sugar. When aphid colonies build, sometimes with scale insects alongside, they let the residue fall over the seating and paving below. A firm jet of water clears the colonies, garden allies like lady beetles and lacewings tidy up the rest, and the film lifts once the honeydew stops.
Fix:
- Hose aphids off with a strong jet of water
- Encourage beneficial predators such as lady beetles and lacewings
- Apply insecticidal soap or horticultural oil to accessible foliage for severe infestations
- Sooty mold disappears on its own once the honeydew source is controlled
A summer canopy worn down to fine lacework
Japanese beetles graze away the soft tissue and leave the veins standing, so the canopy takes on a lacy, worn look from June to August. On a young tree set near a patio or path, an early-morning round tipping the beetles into soapy water keeps it presentable. A mature linden carries the season without concern, refilling its crown on its own, so leave the pheromone traps out of it, since they only summon more.
Fix:
- Hand-pick or knock beetles into soapy water in the early morning on smaller trees
- Tolerate damage on large established trees, which recover
- Avoid Japanese beetle pheromone traps, which attract more beetles
Leaves that read stippled, spotted, or lightly browned
A tired-looking canopy can trace to a short list of causes. Lace bugs, basswood thrips, or spider mites stipple the leaves and leave dark fecal specks beneath, while fungal leaf spots appear as clean lesions through a wet season. Raking up the fallen leaves lowers the spore count, a rinse of the canopy in dry spells eases the mites, and the rest is best left alone, since it stays cosmetic.
Fix:
- Rake and dispose of fallen leaves to reduce fungal spores
- Hose down foliage to dislodge mites in dry spells
- Most leaf spot is cosmetic and needs no treatment
Toxicity
For a home with pets, the news is easy: linden is completely safe. The ASPCA lists it as non-toxic to cats, dogs, and horses, and no part of the tree holds a poisonous compound. The fragrant flowers are even dried for a calming tea, and the young leaves are tender enough to eat.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A cat that wanders the garden is in no danger here, since the ASPCA lists linden as non-toxic to cats. A large mouthful of any greenery may bring passing stomach upset, but the tree holds no poison.
Dogs None
A dog with the run of the yard is equally safe, since the leaves, bark, and flowers carry no toxic principles. One that mouths a fallen branch will be perfectly fine.
Horses None
Horses may browse a linden without harm, and the species holds its place on the ASPCA non-toxic list for them. The young leaves and flowers count as safe forage.
Rabbits Safe
Rabbits may chew the leaves and twigs with no toxic risk in play. Linden is a familiar browse plant, and the tender spring growth is entirely safe for them.
Livestock Safe
Cattle, goats, and sheep may graze the foliage in safety, since the tree holds nothing that troubles them. Linden has long been cut for fodder without incident.
Birds Safe
Birds nest in the canopy and forage around the flowers without any risk. The seeds and buds present no toxic threat.
People Safe
Linden is safe for people, and the fragrant flowers are dried for a soothing tea while the young leaves are tender enough to eat. Not a single part of the tree needs avoiding.
No special handling precautions; honeydew from aphids can make surfaces under the tree sticky but is not toxic.
Varieties
A handful of linden forms are worth knowing before you choose, from compact native selections to silver-leaved relations. These are the ones that turn up most in home gardens and along the street.
Tilia americana 'Redmond'
A tighter, more pyramidal reading of the native tree that settles near 40 to 60 feet, it lends itself to formal shade and a composed streetscape.
Tilia cordata 'Greenspire'
A littleleaf linden with small heart-shaped leaves of 1 to 3 inches beneath a dense oval crown, it is a favored, city-proof street tree from Europe outward.
Tilia tomentosa
The silver linden turns its dark green leaves to reveal white woolly undersides on a passing breeze, so an avenue of them seems to shimmer along the walk.
How to propagate
Linden can be started several ways to suit the goal, from the patience of seed to grafting that holds a named cultivar to the suckers the tree offers up freely.
SeedDemanding
Sow cleaned seed outdoors in fall, or stratify for sowing in spring · 1-2 years or more to germinate
Raising linden from seed is a slow indulgence. The seeds wear a hard coat and a double dormancy, so even with warm-then-cold stratification they may rest for one to two years before rising, and they come up slow and uneven. Sow cleaned seed outdoors in fall, or stratify it for a spring sowing, and set your expectations for the long game.
GraftingDemanding
Late winter for bench grafting or summer for budding · 1 growing season to take
Named cultivars such as 'Redmond' and 'Greenspire' will not come true from seed, so growers graft or bud them onto seedling rootstock to hold the form. Bench graft in late winter or bud in summer, and the union settles over a single growing season.
LayeringModerate
Spring · 1-2 years to root
Basswood offers its own suckers and sprouts from the base, an easy clone waiting to be used. In spring, pin a low branch to the ground to layer it, or lift a rooted sucker, and allow it one to two years to build a root system of its own before it moves.
Myths
Linden trees are poisonous to dogs and cats.
The ASPCA lists linden as non-toxic to dogs, cats, and horses, with no toxic principle anywhere in the tree. A pet that overindulges on any plant may feel a mild stomachache, but there is nothing poisonous about a linden.
The sticky black coating on basswood leaves is a disease that is killing the tree.
The film is only aphid honeydew hosting a harmless sooty mold that feeds on the sugars. It reads worse than it is, since it is purely cosmetic, and it clears once the aphids are handled. A settled tree comes to no harm from it.