Japanese Snowbell Tree (Styrax japonicus)

Japanese snowbell trees (Styrax japonicus) are easy-to-care-for, compact, spring-blooming trees. Due to all of these things, they are perfect for moderately sized, low-maintenance beautifying in places such as parking lot islands and along property borders. Keep reading to learn more Japanese snowbell information, such as planting Japanese snowbell trees and subsequent Japanese snowbell care.

I. Appearance and Characteristics

Styrax japonicus (野茉莉, also エゴノキ, egonoki), also known as the Japanese snowbell, is a species of flowering plant in the family Styracaceae, native to Korea, Japan, and Southern China.

Styrax japonicus is a member of the Styracaceae family, with the authority of Siebold & Zuccarini. Styrax is a genus whose members produce aromatic resins. The Latin specific epithet japonicus means “from Japan”.

The Japanese common name, egonoki (野茉莉, エゴノキ), originates from how the fruit annoys the throat and tongue when put in the mouth — egui (えぐい) or egoi (えごい) describes something that evokes a repulsive, bitter flavor.

The appearance of Styrax japonicus ranges from a large shrub to a small tree.

• Leaves

Leaves are simple in alternate arrangement. They are upward-facing with an oblong shape, dark green and shiny.

• Flowers

The flowers of S. japonicus are pendulous and arranged in a raceme inflorescence. When in bloom, they evoke a light fragrance. The petals are commonly colored white; however, the petals of the ‘Pink Chime’ cultivar is pink. The five-petaled, bell-shaped corolla is around 2-3 cm long and typically blooms in late spring. The corolla is surrounded by 5-toothed calyx. They are perfect and perigynous with prominent yellow stamens.

• Fruit

The gray-green drupe-like capsule fruits of S. japonicus are around 2 centimetres (0.79 in) long, appearing around August and September. Long stalks extend from each drupe and attach with star-shaped calyx. Each fruit contains one seed.

II. How to Grow and Care

Sunlight

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.

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.

Watering

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.

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.

Fertilizing

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.

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.

Propagation

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

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.

• Starting with a nursery-grown tree, fill your container 1/3 full with quality potting soil.
• Lift the tree from its starter pot or remove burlap or other material from the rootball and lightly shake off excess soil.
• Set the tree on top of the soil and spread out the roots.
• 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.
• 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.

Pests and Diseases

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.

Common Problems

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.

III. Uses and Benefits

• Ornamental uses

The masses of flowers present on a blooming tree lead to the pronounced prevalence and popularity of S. japonicus cultivars. It is thought that the tree’s abundant flowers, along with its lavish foliage and striated bark, contributed to its successful introduction from Eastern Asia to Western gardens.

However, S. japonicus has a relatively limited flowering period; a single flower has a blooming period of 4-5 days before wilting and a group of flowers last around 2 weeks, prompting studies investigating how to prolong the flowering period.

• Medicinal uses

Chinese traditional medicinal use of S.japonicus has phamacological evidence, such as the anagesic effects used to treat toothaches and sore throats and antitussive purposes to treat coughs.

• Cultural Use

Along with its cultivation for ornamental use, S. japonicus has been used for its material and chemical contents. The hardwood was used to compose umbrella ribbing and pieces for shogi (a Japanese strategy board game).

The dried pericarp of young fruit has been used to make washing soap, due to saponin contents. It also contains large amounts of egosaponin, a poisonous agent that has been used in East Asian traditional fishing to stun fish and make them easier to catch.