Tree · Cornaceae
Kousa Dogwood
Cornus kousa
A small tree carrying star-shaped white bracts, pinkish-red fruit, and mottled peeling bark through the seasons.
Full sun
Every 5–10 days
USDA 5–8
15–30 ft · 4.6–9.1 m
Overview
Kousa dogwood shows a different face in every season. Its late-spring display is built from four pointed, star-shaped bracts, and because they open after the leaves are out, unlike the native flowering dogwood, each pale bract sits framed against the fresh green of the canopy. By late summer the branches carry rounded pinkish-red fruit, the plump, raspberry-like aggregate that birds strip and people can eat.
It is a small tree, reaching 15 to 30 feet (4.6 to 9.1 m) tall and roughly as wide, its branches drawn up into a vase shape when young that broadens and rounds with the years. The growth is slow, so its frame thickens gradually. The finest detail sits on the trunk itself: as it ages the bark flakes away in patches, leaving a mottled, camouflage-like mix of tan, gray, and brown that stands out most sharply in the bare light of winter.
This is the tree often chosen over Cornus florida for its tougher constitution. It resists the anthracnose and borers that scar the native dogwood, needs little once its roots take hold, and endures cold to -20°F (-29°C). Set in decent soil and kept in steady moisture, it largely carries itself.
Care
The short version: full sun to part shade in rich, slightly acidic, well-drained soil, kept evenly moist so the leaves stay full through summer heat. Mulch the roots, prune almost never, and let this slow grower thicken its frame at its own pace.
Light
Kousa dogwood grows best in full sun to part shade. Full sun draws out the heaviest set of bracts, but in hot regions a little afternoon shade spares the leaf blades from scorching at midsummer.
Water
Keep the soil at a steady, medium moisture, watering every 5 to 10 days and more often through a hot, dry spell so the leaves stay full rather than crisping at the edge. Once established it endures drought better than the native dogwood, though its roots will not take waterlogged ground.
Soil
Plant it in rich, humusy, well-drained loam on the acidic to neutral side, ideally a pH of 5.5 to 7.0. Compost worked into the ground and an acidic organic mulch on the surface keep the roots cool and fed.
Temperature
The tree is hardy across a wide range, from -20°F to 95°F (-29°C to 35°C), spanning USDA zones 5 through 8. It takes hard winters in stride and only falters where summers stay relentlessly hot and dry.
Humidity
Ordinary outdoor humidity suits it, so there is no figure to hit. What tells on the leaves is air movement, since crowded, stagnant growth is what lets a powdery film of mildew settle on the blades.
Feeding
Feed once in early spring with a balanced slow-release fertilizer, or simply top-dress with acidic compost or mulch. This slow grower has modest needs and shows little response to being pushed.
Pruning
Prune as little as possible. Cut out only dead, damaged, or crossing branches, and do it just after flowering in late spring to early summer so next year's flower buds are not lost.
Repotting
A kousa dogwood is rarely held in a container for long, so repotting almost never comes up. If one is potted and its roots begin circling or pushing through the drainage holes, move it to a larger container or, better, into open ground.
Size & spacing
Expect a mature tree of 15 to 30 feet (4.6 to 9.1 m) tall with a spread to match. Give it that much open room so the broad, rounded crown can fill out and air can move between the branches.
When to plant
Kousa dogwood is a woody tree planted once and kept for decades. Set it out in spring or fall so the roots can take hold before the next round of heat or hard frost, and watch for the star-shaped bracts in late spring and the pinkish-red fruit ripening from late summer into early fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: spring or fall
- Harvest: Blooms late spring to early summer (May to June), after leaves emerge; pinkish-red edible fruit ripens late summer to early fall.
Hardiness
USDA hardiness zones: 5–8
Temperature: down to -29°C
Troubleshooting
Most kousa dogwood trouble is written across the leaves, and the cause is usually the site or the weather rather than the tree. The look of the damage tells the story: dry, browned rims point one way, tight angular flecks another. Match what you see on the blades below, then act before it spreads.
Crisp brown rims and curled blades in high summer
When the leaf margins turn dry and brown and the blades curl inward, the cause is leaf scorch, which shows up on a tree in a hot, sunny spot that cannot draw up enough water to keep its foliage full. The browning bites first at young trees, whose shallow roots run short soonest. Deep watering through dry spells, a 2 to 3 inch (5 to 8 cm) ring of mulch, and afternoon shade in fierce summers keep the leaves whole.
Fix:
- Provide deep, regular watering during heat and drought
- Apply a 2-3 inch organic mulch layer to conserve soil moisture and keep roots cool
- Site in partial afternoon shade in hot climates
A chalky white haze across the leaf faces
A powdery white to grayish film sitting on the upper leaf surface is powdery mildew, a fungus that thrives in humid air, deep shade, and the stillness of crowded growth. It can pucker and warp the blades but seldom does harm that lasts. Thinning the canopy to let air slip through, stripping off the most heavily filmed leaves, and a labeled fungicide only in a severe case clear it away.
Fix:
- Improve air circulation by thinning and proper spacing
- Remove and dispose of affected foliage
- Apply a labeled fungicide if infection is severe
Angular brown to purple flecks scattered on the blades
Small, sharp-cornered spots in brown to purple, each ringed by a darker margin, mark septoria leaf spot, a fungus that surfaces later in the season after the foliage has stayed wet a long while. Where scorch dries the whole rim, this one prints tight, angular flecks across the face of the leaf. Raking up the fallen leaves, keeping water off the foliage, and a labeled fungicide only when leaf drop turns heavy keep it in hand.
Fix:
- Rake and dispose of fallen infected leaves
- Avoid overhead watering and wetting foliage
- Apply a labeled fungicide only if defoliation is significant
Toxicity
The safety picture is a clear one. Kousa dogwood is non-toxic to pets, livestock, and people, and its ripe pinkish-red fruit, soft and sweet inside, is good to eat. No part of this tree needs fencing off, and a curious pet sampling a leaf is no cause for worry.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats Safe
No part of the tree is toxic to cats. A cat that bites into a leaf may get a brief, mild stomach upset, no different from any non-food plant, and nothing beyond that.
Dogs Safe
The leaves, the bark, and the fallen fruit hold no real risk for dogs. A gulped mouthful might stir a short bout of digestive upset that clears on its own.
Horses Safe
Horses come to no harm from the tree, the green foliage and the ripe fruit alike. There is nothing here to warrant fencing it from a paddock.
Rabbits Safe
Rabbits can browse the leaves safely. As with any fresh green, ease it in slowly so a sudden change of diet does not loosen their digestion.
Livestock Safe
Cattle, goats, and sheep can graze around the tree untroubled, as it holds no toxin that reaches them.
Birds Safe
Birds pick over the ripe fruit and carry the seed off with them. The tree offers a food source rather than a hazard.
People Safe
The ripe pinkish-red fruit is good to eat, with soft, sweet flesh inside, and nothing else on the tree poses danger. The thin skin and gritty seeds are usually left behind.
No special handling required; ingestion of plant material may rarely cause mild, transient gastrointestinal upset as with any non-food plant.
Varieties
Most kousa dogwoods sold are named selections, singled out for the color of their bracts, the markings on their leaves, or their toughness. These are the ones worth knowing by name.
Milky Way
A free-flowering selection, often listed under var. chinensis, that loads its branches with creamy-white bracts and then a heavy set of fruit.
Wolf Eyes
A compact, slow grower whose green blades are edged with a crisp band of white, the variegation that makes its foliage read so bright.
Satomi
Marked out by bracts in deep pink to rose rather than the species' usual white.
Cornus × rutgersensis (Stellar series)
The Rutgers hybrids of Cornus florida and Cornus kousa, among them Aurora, Constellation, and Stellar Pink, bred to shrug off anthracnose and borers.
How to propagate
Kousa dogwood can be increased several ways, from slow and variable seed to the simple layering trick that asks almost nothing of you. Which route you take depends on whether you need an exact copy of a named tree.
SeedModerate
Sow cleaned seed in fall or after cold-moist stratification in late winter. · Several years to reach flowering size
Wash the pulp from the seed, then either sow it in fall or give it a cold-moist stratification before sowing in late winter, which stirs it into germinating. A seedling wants several years to reach flowering size, so patience is part of the job. Seedlings come up variable, so they will not reliably match the parent tree.
Stem cuttingsModerate
Take softwood to semi-hardwood cuttings in late spring to summer. · One growing season to root and establish
Take softwood to semi-hardwood cuttings from late spring into summer, dip the cut ends in rooting hormone, and hold them under mist. They root across a single growing season, and kousa cuttings strike more readily than those of many other trees.
GraftingDemanding
Graft named cultivars onto seedling rootstock in late winter or summer. · One to two seasons to establish union
The demanding route grafts or buds a named cultivar onto seedling rootstock in late winter or summer. The union knits together over one to two seasons. It is how nurseries keep cultivars true to type, since seed-grown offspring will not be.
LayeringEasy
Layer low flexible branches in spring. · One to two growing seasons to root
The easiest method for a home gardener is to layer a low, supple branch in spring, pinning it to the soil until roots form. Rooting takes one to two growing seasons, after which the branch can be cut free and the new plant lifted.
Myths
Kousa dogwood catches anthracnose and borers just as badly as the native flowering dogwood.
Cornus kousa stands up far better to both dogwood anthracnose and the dogwood borer than Cornus florida does. This is the tree to plant where anthracnose has taken hold before, which is just why it is so often recommended as a replacement.
The red raspberry-like fruit is poisonous and shouldn't be eaten.
The pinkish-red fruit is edible, its flesh soft and sweet once it fully ripens. Birds and other wildlife take it too, so it doubles as food and as a draw for the garden.