In short
- Flowers late, in June, after the leaves have emerged — later than most dogwoods.
- The white "flowers" are actually four pointed bracts; the true flowers are small and greenish.
- The pinkish-red, raspberry-like compound fruits are edible and ripen in September and October.
- Resistant to dogwood anthracnose, which afflicts the American flowering dogwood (Cornus florida).
- Requires humus-rich, free-draining, slightly acidic soil and a sunny or partly shaded position.
Botanical data
- Family
- Cornaceae (Cornaceae)
- Height
- 4–7 m
- Width
- 3–6 m
- Habit
- Spreading
- Growth rate
- Slow
- Position
- Full sun, Partial shade
- Soil
- Humus-rich, Loamy, Sandy
- pH reaction
- pH 5.5–7
- Moisture
- Moderate, Moist
- Bloom
- June–July
- Hardiness
- USDA 5a–8b
- Propagation
- From seed, From cuttings, By layering
Characteristics
The kousa dogwood forms a small tree or large, multi-stemmed shrub. Young specimens have a vase-shaped, upright habit; with age the crown spreads into a broad, dome-shaped and distinctly tiered form, with horizontally arranged layers of branches. The leaves are opposite, ovate to elliptic, entire, with a wavy blade and the arching venation typical of dogwoods; dark green in summer, they turn scarlet, purple and orange in autumn. What looks like a large, four-petalled white flower is in fact a set of four pointed bracts about 3-5 cm long; the true flowers are small, greenish-yellow blooms clustered in a spherical head at the centre of the bracts. Flowering falls in June (in cooler positions it continues into early July), thus later than in most dogwoods and after the leaves have emerged; the showy bracts persist for several weeks, gradually shifting from green to pure white, and in some cultivars to pink. The fruit is a spherical, raspberry-like compound fruit 1.5-2.5 cm in diameter, pinkish-red, hanging on a long stalk and ripening in September and October. The bark of older trunks flakes off in patches, revealing a mosaic of shades of brown, grey, cream and pink — an additional ornamental asset, visible especially in winter.
Popular cultivars
- ‘Satomi’
- The most popular pink-flowering cultivar — the bracts are intensely pink, darker in cooler positions. In autumn the leaves turn red; the habit is broad, reaching about 4-6 m.
- ‘Milky Way’
- A cultivar from the var. chinensis group, flowering abundantly — the shoots are densely covered with creamy-white bracts. It sets numerous fruits; the habit is upright, rounding out with time.
- ‘China Girl’
- Also from var. chinensis, prized for early and abundant flowering even on young specimens. White bracts, good fruiting and a broadly conical habit.
- ‘Wolf Eyes’
- A cultivar with variegated leaves — green with a broad, creamy-white margin, pinkish-red in autumn. Compact and slow-growing, up to about 3 m; good for smaller gardens and for partial shade.
- ‘Gold Star’
- Leaves with a distinct, golden-yellow blotch in the centre of the blade, contrasting with the green margin. White bracts; broad, tiered habit — a cultivar that is colourful also outside the flowering period.
Growing and care
Watering
It has a shallow root system and tolerates drying out poorly; during hot, dry spells it needs watering, especially in the first years after planting.
Fertilizing
Moderately; on humus-rich soil, compost and a bark mulch suffice, keeping the reaction slightly acidic.
Planting
Humus-rich, free-draining soil, adequately moist and slightly acidic to neutral; a sunny or lightly shaded position, sheltered from dry winds. Avoid strongly calcareous and dried-out soils.
Pruning
Minimal pruning — the species builds a fine, tiered habit on its own; remove only dead, diseased and crossing shoots.
Companion plants
Good companions
Obie rośliny lubią próchniczną, lekko kwaśną i przepuszczalną glebę oraz osłonięte, półcieniste stanowisko — klasyczne zestawienie w ogrodzie leśnym i japońskim.
Funkia dobrze rośnie w cieniu rzucanym przez koronę derenia i wypełnia przestrzeń u jego stóp, znosząc te same, wilgotne warunki glebowe.
Bad companions
Dereń kousa źle rośnie na glebach zasadowych i przesuszonych, więc sąsiedztwo roślin o przeciwnych wymaganiach zmusza do kompromisu szkodliwego dla derenia.
The evidence level indicates whether the relationship is backed by research, observation, or gardening tradition.
Diseases and pests
A white, powdery coating on leaves, shoots and buds. The leaves turn yellow, become deformed and drop prematurely. The coating develops on both sides of the leaf blade, is often clearly visible from above, and can easily be rubbed off with a finger — it is the superficial mycelium of an ectoparasite that draws nutrients from the epidermal cells by means of feeding structures (haustoria). At first single, round, white spots appear, which in time merge and cover the entire leaf surface and the young growth. Young leaves and the current season's shoots are the most susceptible; heavy infection causes them to pucker, stiffen and stop growing, and on buds it leads to deformation or death of the flowers. On the fruit of some species (gooseberry, apple, cucurbits) the coating leaves russeting or a corky skin. Towards the end of the season, small, dark fruiting bodies (chasmothecia, formerly called cleistothecia) — the pathogen's overwintering structures — appear within the coating. The disease affects many plants, including roses, oak, privet, lilac, cucurbits, cereals, grapevine, apple, gooseberry, phlox and coneflowers, with each of these hosts being infected by a specialised species of fungus.
AphidsSmall (1–3 mm) soft-bodied insects, green, black or pink, feeding in clusters on young shoots and the underside of leaves. They excrete sticky honeydew. The diagnostic feature that distinguishes aphids from other small sucking insects is the pair of siphunculi (tubular projections) at the rear of the abdomen together with a tail-like cauda; a single colony usually holds wingless forms (parthenogenetic females) alongside winged migrants that fly onto new plants in summer. In summer aphids reproduce parthenogenetically and viviparously over many generations, so the population builds up explosively; in autumn many species produce a sexual generation that lays overwintering eggs on the host, and host-alternating species move between a winter host (often a tree or shrub) and a summer host (a herbaceous plant). Feeding symptoms include curling, crinkling and distortion of young leaves, stunted growth, yellowing, and the shedding of buds and fruitlets. Abundant honeydew coats the leaves, and the sooty mould fungus that develops on it forms a black film which limits photosynthesis; the honeydew is fed on by ants, which in return defend the colony against predators. Aphids are also important vectors of plant viruses (mosaics among them), transmitting them from plant to plant even during a brief probing puncture.
Spider mitesTiny (0.3–0.5 mm) arachnids, hard to spot with the naked eye, feeding on the underside of leaves. Symptoms: fine, pale speckling (feeding punctures); over time the leaves turn grey, yellow and dry out. Under heavy infestation a fine webbing becomes visible. Warm, dry air favours their development — a common problem for houseplants in winter near radiators. Spider mites are not insects but mites of the family Tetranychidae — adults have 8 legs (larvae only 6). The most common in cultivation is the two-spotted spider mite (Tetranychus urticae): yellowish-green females carry two dark spots on the sides of the body, while overwintering females turn orange-red. In orchards the fruit tree red spider mite (Panonychus ulmi) is frequent, whose red eggs overwinter in clusters on the bark of the shoots. Feeding mechanism: the mites puncture the cells of the epidermis and mesophyll on the underside of the leaf and suck out their contents, and the emptied cells fill with air — hence the characteristic, silvery-grey, fine speckling visible from the upper side of the blade (resembling a mosaic discolouration). At high numbers the leaves turn brown, curl and drop prematurely, and the whole plant weakens and loses its growth. Dense webbing spun between the leaves and shoot tips appears only under an advanced attack and is a sign of the risk of the pest spreading to neighbouring plants. The development cycle is very fast in warmth and drought — at a temperature of 25–30°C a single generation can be completed in 1–2 weeks, hence the numerous generations per season and the rapid, exponential build-up of the population. Females lay spherical, transparent eggs on the underside of the leaves. Fertilised females overwinter (in bark crevices, leaf litter and plant debris) or — in the fruit tree red spider mite — the eggs on the bark. Early infestation is easy to miss; diagnosis is helped by shaking a leaf over a white sheet of paper (moving specks become visible) or examining the underside of the leaf with a magnifying glass.
Toxicity
| For whom | Level | Notes |
|---|---|---|
| Humans | None | — |
| Dogs | None | — |
| Cats | None | — |
History and origin
The kousa dogwood comes from East Asia — from Japan, Korea and China, where it grows in open mountain forests. It reached the gardens of Europe and North America in the second half of the 19th century and quickly gained recognition as a tree with an exceptionally long season of interest. The continental, Chinese variety (Cornus kousa var. chinensis), with larger and more abundantly produced bracts, was popularised in the West at the beginning of the 20th century by the British plant collector Ernest Henry Wilson. The Japanese name for the species, yamaboshi, means "mountain monk" and alludes to the white bracts resembling the headwear of a wandering monk; the element kousa derives from a regional Japanese name for the plant. Unlike the American flowering dogwood (Cornus florida), the species has proved resistant to dogwood anthracnose — a fungal disease that from the end of the 20th century decimated natural populations of C. florida in the United States — which is why the kousa dogwood and its hybrids increasingly replace the flowering dogwood in ornamental plantings.
Uses
In the garden the kousa dogwood is planted above all as a specimen, clearly visible up close, where one can admire in succession the bracts, the fruits, the autumn leaf colours and the exfoliating bark. It works well in small and medium-sized gardens, beside terraces, in Japanese-style gardens and in loose groups at the edge of taller plantings. The best position is sunny or lightly shaded during the midday hours, sheltered from dry winds; in full shade the plant flowers less well. It requires humus-rich, free-draining, adequately moist and slightly acidic to neutral soil — on strongly calcareous and dried-out soils it grows poorly. Because of its shallow root system, it is worth mulching the zone beneath the crown with bark and avoiding deep digging. It combines well with acid-loving plants of similar requirements: rhododendrons, azaleas, hostas and ferns, which fill the space at its feet. The fruits are edible, with sweet, mealy flesh, but the hard, grainy skin and numerous seeds mean they rarely go to direct consumption. The species is not suitable for clipped hedges or for sunny, windy front gardens.
Trivia
- The Japanese name yamaboshi ("mountain monk") alludes to the white bracts resembling the hood of a wandering monk.
- Unlike the American flowering dogwood (Cornus florida), the kousa dogwood is resistant to the destructive dogwood anthracnose.
- The large, white "petals" are in fact bracts (floral leaves); the true flowers are small and gathered in a spherical head in the centre.
- The raspberry-like fruits are edible — they have sweet, slightly mealy flesh, but a hard, grainy skin and numerous seeds; birds eat them readily.
Frequently asked questions
How does the kousa dogwood differ from other dogwoods?
It flowers later — in June, after the leaves have emerged, whereas the Cornelian cherry flowers at the turn of winter and spring. It also has exceptionally large, white bracts surrounding small flowers, ornamental raspberry-like fruits and exfoliating bark. Unlike the American flowering dogwood, it is resistant to dogwood anthracnose.
Are the fruits of the kousa dogwood edible?
Yes. The pinkish-red, raspberry-like compound fruits are edible and have sweet, slightly mealy flesh. They rarely reach the table, however, because the skin is hard and grainy and there are many seeds in the flesh. Most often they are eaten by birds.
When does the kousa dogwood flower?
In June; in cooler positions flowering continues into early July. This is considerably later than in most dogwoods, and the showy white bracts remain on the plant for several weeks.
What soil and position does the kousa dogwood require?
Humus-rich, free-draining, adequately moist and slightly acidic to neutral soil. It tolerates strongly calcareous soils and drying out poorly. It grows best in sun or light partial shade, sheltered from dry winds; in deep shade it flowers poorly.
Why is my kousa dogwood not flowering?
Most often it is a matter of age — young specimens only begin to flower abundantly a few years after planting. Flowering is also weakened by too deep shade and an excess of nitrogen in fertilising. Because the plant flowers late, spring frosts are rarely a problem here.
Sources
- Plants of the World Online (POWO)Database (GBIF, POWO…)
- RHS — Cornus kousaInstitution / botanical garden
- Missouri Botanical Garden — Cornus kousaInstitution / botanical garden
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