How to Grow and Care For Japanese Snowbell (Styrax japonicus)

Elegant, showy, and resistant to pests and disease, Japanese snowbell tree (Styrax japonicus) is a little-known gem with potential in both urban and rural landscapes. This small, compact tree blooms in May and June displaying clusters of fragrant, bell-shaped, white or pink blossoms and glossy, dark green foliage. Long-lasting fruits appear in autumn and mature trees develop fissured bark adding winter interest.

Japanese snowbell is a good choice to plant around patios and in beds or shrub borders providing dappled sunlight for shade-loving garden plants and flowers. Dwarf varieties can also be grown in containers.

Read this guide to learn more about the lovely Japanese snowbell tree and how to fit one into your landscape plan.

Japanese Snowbell Care

Once your Japanese snowbell tree is established, little maintenance is required other than occasional pruning to develop the desired shape and size. Early growth creates a vase-like form in most cultivars extending to a more rounded crown as these trees mature.

Fruits drop in autumn and early winter but seldom create a need for extensive clean-up. Plant in a location sheltered from high winds.

Light

Plant this small, ornamental tree where it will receive six hours of bright, direct sun exposure daily. In climates with hot summers (90 degrees°F ) two hours of afternoon shade protect foliage from sunburn. Insufficient light causes leaves to yellow and drop.

Soil

Japanese snowbell is tolerant of clay and sand but humus-rich loam that drains well delivers the healthiest growth. Soil pH should range from neutral to slightly acidic with ideal levels between 5.5 and 6.5.

Water

This tree has moderate moisture needs but won't tolerate drought conditions. Water newly planted saplings weekly during the first year to keep soil consistently damp but not soggy. Irrigate deeply with a gallon of water every one or two weeks depending on rainfall in your area.

Once established, plan to water as needed during the summer months. A 3- to 4-inch layer of mulch retains soil moisture and discourages competing weeds.

Temperature and Humidity

Japanese snowbell adapts well to average temperatures in USDA zones 5 through 8 and parts of zone 9. Some varieties tolerate temperatures as high as 95°F as long as afternoon shade is provided. Others survive temperatures as low as 5°F but extreme fluctuations in temperate could be damaging to this tree.

Mulching helps prevent root damage in colder climates with late spring frosts. Humidity levels generally aren't an issue however extended periods of hot, moist air can lead to fungal problems.

Fertilizer

Fertilizer is optional for trees grown in good soil with several suggestions for supplemental feeding. Some growers recommend withholding fertilizer until young trees establish a strong root system, then applying a balanced, water-soluble formula in early spring before new growth begins. To encourage blooming choose a product slightly higher in phosphorous.

Types of Japanese Snowbell

• S. japonicus 'Carillon': Weeping cultivar with white flowers on cascading branches. Slow growers mature at 10 feet tall. Hardy in USDA zones 5 to 8.
• S. japonicus 'Crystal': This cultivar forms a more columnar shape with black-green foliage and white flowers on purple stems. Hardy to USDA zone 5.
• S. japonicus 'Emerald Pagoda': Young trees display upright pyramidal growth with large white flowers and leathery, vibrant green leaves. Hardy to USDA zone 5
• S. japonicus 'Evening Light': Leaves emerge as purple-maroon turning to a maroon-green hue. White flowers feature maroon sepals. Growth is often multi-stemmed with trees maturing at 15 feet tall and 10 feet wide. Hardy to USDA zone 5
• S. japonicus 'Pink Chimes': Fragrant light pink blossoms appear in June on this cultivar with a shrubby growth habit. Hardy in USDA zones 5 to 8.

Pruning

Japanese snowbell trees grow slowly so pruning requirements are minimal and done in late winter or early spring before buds appear. Remove low branches from young trees to encourage crown development and reduce multi-stemmed cultivars to a single stem to create a tree form.

Inspect your tree annually and remove dead, diseased, and damaged branches. Otherwise, gentle pruning about every three years is usually adequate to retain the desired shape.

Propagating Japanese Snowbell

New cultivars of Japanese snowbell are coming to market as this ornamental gains popularity with homeowners. It isn't legal to propagate trademarked cultivars so plan to purchase additional nursery-grown seedlings.

Although other varieties can be propagated in summer with softwood cuttings, success is limited with slow development. It can take several years to get a reliable transplant.

Potting and Repotting Japanese Snowbell

Several dwarf varieties of Japanese snowbell are suited to growing in containers maturing at just 8 to 10 feet tall and 3 to 4 feet wide. Select a pot with plenty of drainage holes and at least twice as wide and deep as the rootball. Plastic or glazed ceramic pots work best for retaining soil moisture. Potting and repotting is best done in early spring.

1. Starting with a nursery-grown tree, fill your container 1/3 full with quality potting soil.
2. Lift the tree from its starter pot or remove burlap or other material from the rootball and lightly shake off excess soil.
3. Set the tree on top of the soil and spread out the roots.
4. Start backfilling in around them with more potting soil until it reaches the original soil line on the trunk. Watering as you go helps settle the soil.
5. Water thoroughly. Remember that potted trees require more frequent irrigation.

Slow-growing Japanese snowball requires potting up only about every three years or when roots begin to extend through the drainage holes. Choose a new, larger container twice the width and depth of the larger rootball and follow the steps above.

Overwintering

In colder climates, protect Japanese snowbell roots with a thick layer of mulch. Move potted trees to a sheltered location and insulate pots in areas where temperatures dip below 5°F or the low temperature tolerated by your cultivar.

Common Pests and Plant Diseases

Japanese snowbell is unaffected by common pests and plant diseases. Ambrosia beetles may be attracted to plants weakened by environmental stresses like extreme temperatures.

Prevent infestations by maintaining healthy growth and knocking down pests as soon as you spot them with a strong spray from a garden hose. There are no chemical controls for Ambrosia beetles, although pyrethrin is sometimes applied in worst cases.

How to Get Japanese Snowbell to Bloom

Bloom Months

Japanese snowbells bloom in late spring to early summer. Depending on variety, flowers appear between May and June lasting for several weeks.

What Do Japanese Snowbell Flowers Look and Smell Like?

Lightly fragrant, white or pink, 3/4 inch flowers appear in masses on most varieties although new cultivars are being developed with larger flowers. Bell-shaped blossoms are pendulous, dangling below branches from green or purple stems with some white varieties featuring purple sepals.

Foliage grows in an upright orientation on upper branch surfaces which showcases the flowers below. This tree is most valued for its spring floral display with mixed opinions on flower fragrance— some say pleasant, odd, or coarse. It is highly attractive to bees and other pollinators.

How to Encourage More Blooms

Healthy trees bloom easily and profusely without additional fertilizer. You can, however, boost blooms with a high-phosphorous NPK fertilizer in early spring.

Caring For Japanese Snowbell After It Blooms

Japanese snowbell blossoms drop naturally and seeds develop fruits called drupes in late summer and early autumn. There is no need to remove flowers.

Common Problems With Japanese Snowbell

This is an easy-care, ornamental hardwood that is nearly problem free. Issues that may come up are likely due to inadequate watering or environmental causes.

Yellowing Leaves

Foliage can become chlorotic, with a faded, yellowing color, when soil is too alkaline, temperatures are too high, or soil gets too dry. Check the soil and lower pH before planting if necessary.

Make sure the variety you choose is adapted for your growing zone and water new plantings weekly for the first year. Apply mulch to hold in soil moisture and discourage weeds.

Lack of Blooms

A deficit of flowers is likely caused by a mistake with fertilizer. Planted in humus-rich, well-drained soil, these trees do not require supplemental feeding. Fertilizers with too much nitrogen result in overabundant foliage at the expense of flowers.