Kousa Dogwood (Cornus kousa) is a small deciduous tree that is native to Japan, Korea, and China. It is also called Chinese Dogwood, Korean Dogwood, or Japanese Dogwood. Kousa Dogwood is popular in gardens and landscapes due to its stunning flowers, versatility, and resistance to diseases that affect other dogwood species.
Background on Kousa Dogwood
Kousa Dogwood typically grows 15-30 feet tall and wide, with a rounded, multi-stemmed form. The foliage emerges reddish-purple in spring, darkening to green through summer, and turns red-purple in fall. The tree features delicate white or pinkish flower bracts in late spring to early summer. The flowers give way to red fruits that resemble raspberries, which are edible although not particularly tasty to humans. Birds like to eat the fruits.
This species is adaptable to various soil types and lighting conditions. It can grow in full sun to part shade. Kousa Dogwood prefers moist, well-drained soil but has some drought tolerance once established. It has no serious insect or disease problems, unlike the native flowering dogwood (Cornus florida) which is susceptible to dogwood anthracnose, a fungal disease.
Flower Color Varieties
One of the most outstanding features of Kousa Dogwood is its showy flower bracts that appear in late spring or early summer after the leaves emerge. The wild species typically has white bracts with a pink tinge, but through selective breeding there are now many Kousa Dogwood cultivars available with bract colors ranging from white to pink, red, and more.
Here are some of the most popular Kousa Dogwood varieties categorized by flower bract color:
White Flowers
- White Dallas – Large, pure white bracts up to 4 inches wide.
- China Girl – Abundant white blooms.
- Prophet – White with a light pink tinge at the base.
- Wolf Eyes – White with a large green center.
- Radiant Rose® – Creamy white with a light pink tinge.
Pink Flowers
- Pink Champagne – Soft pink bracts.
- Heart Throb – Vibrant pink bracts up to 5 inches wide.
- Prophet – Pink tinged margins.
- Satomi – Rose pink with darker pink veins.
- Summer Fun® – Bright pink bracts.
Red Flowers
- First Lady – Cherry red bracts.
- Red Cascade – Ruby red bracts.
- Satomi – Red tinged margins.
- Radiant Red® – Rosy red bracts.
- Ruth Ellen® – Deep red bracts with white centers.
Blush Colored Flowers
- Elizabeth Lustgarten – Pale blush pink and white bracts.
- Julian – Double layer of soft pink bracts.
- Burgundy Cotton – Red buds open to blush pink blooms.
Multi-Colored Flowers
- Milky Way – White bracts speckled with pink.
- GalileanTM – White petal margins with red centers.
- Samaritan® – Creamy white centers with pink margins.
Timing of Bloom
In addition to varying flower colors, different Kousa Dogwood varieties also bloom at slightly different times. Here is an overview of bloom time for early, mid, and late season varieties:
| Early Bloomers | Mid-Season Bloomers | Late Bloomers |
|---|---|---|
| Milky Way | Prophet | Wolf Eyes |
| China Girl | Red Cascade | Ruth Ellen |
| Samaritan | Satomi | Burgundy Cotton |
In general, Kousa Dogwood blooms after most spring-flowering trees like redbuds, crabapples, pears, and some magnolias. It overlaps with the bloom time of later magnolias, lilacs, and azaleas.
Bloom duration is usually 1-2 weeks for an individual tree. However, by selecting early, mid, and late varieties, it’s possible to extend the decorative flowering display of Kousa Dogwood in the landscape to 4-6 weeks or more.
Flowering Differences Between Tree Age Groups
The abundance and size of Kousa Dogwood flowers can vary quite a bit depending on the age of the tree:
Young Trees
Kousa Dogwood trees typically take 3-5 years after planting to begin flowering. The first flower show may be sparse, and the bracts will be fairly small (1-2 inches wide).
Middle Age Trees
Once established, a Kousa Dogwood enters its most vigorous flowering stage. Trees 5-15 years old produce an abundance of the signature horizontal blooms. The flower bracts reach their maximum size potential, which is usually around 3-5 inches wide depending on variety.
Mature Trees
Flower production may start to decline slowly in trees over 20 years old. The number of blooms is reduced, but the size of the individual flowers remains large on healthy trees. Really old trees may eventually stop flowering altogether.
Factors Impacting Flower Color
Several environmental factors can impact the flower color intensity and presentation on Kousa Dogwood trees:
Sun Exposure
Kousa Dogwood grows best in partial sun or dappled shade where the flowers will develop the deepest, richest colors. Too much shade can cause the flower bracts to appear pale and washed out. Conversely, hot afternoon sun may scorch the flowers or cause the pink/red tones to fade.
Soil Conditions
Rich, slightly acidic, moist soil brings out the brightest most vivid flower colors. Poor soil or drought stress may result in smaller, paler blooms that don’t reach their full color potential.
Temperature
Cool spring temperatures help preserve Kousa Dogwood flower color. Heat waves during bloom time can cause flowers to rapidly decline. Nighttime temperatures below freezing may damage flowers and limit color development.
Pruning Practices
Improper pruning at the wrong time of year can reduce flower bud formation and negatively impact flowering performance. Follow best practices to prune Kousa Dogwood immediately after bloom, not in fall or winter.
Conclusion
Kousa Dogwood comes in a diverse palette of flower colors ranging from white and pink to red, blush, and multi-toned combinations. The many cultivars offer bloom times from early to late spring. While young trees may bloom sparsely, abundant color is achieved on trees 5-15 years old. Provide appropriate growing conditions and pruning practices to maximize flower color potential. With so many options, Kousa Dogwood is sure to bring captivating color to spring gardens and landscapes.