Sinojackia xylocarpa
Common Name: jack tree 
Type: Tree
Family: Styracaceae
Native Range: Eastern China
Zone: 7 to 10
Height: 15.00 to 20.00 feet
Spread: 15.00 to 20.00 feet
Bloom Time: May to June
Bloom Description: White
Sun: Full sun to part shade
Water: Medium
Maintenance: Medium
Suggested Use: Flowering Tree
Flower: Showy
Tolerate: Drought

Culture

Best in acidic, moderately fertile, humus-rich, medium moisture, well-drained soils in full sun to part shade. Plants appreciate some part afternoon shade in hot summer climates. Established plants have some resistance to drought. Propagate by seed or cuttings.

Noteworthy Characteristics

Sinojackia xylocarpa, commonly called jacktree, is a small spreading deciduous tree or large shrub of the Styrax family that typically grows to 15-20' tall. It is native only to Jiangsu Province in China. This tree was first botanically described in 1928, having been discovered growing in the wild near Nanking, China in 1925.

Pendant, star-shaped, white flowers (to 1" wide) with yellow center stamens cover this tree with bloom in spring (April-May). Flowers appear in 3 to 5-flowered cymes, with each flower having 5-7 petals. Flowers give way to egg-shaped woody drupes (to 3/4” long) that ripen in July-September. Obovate-elliptic, short stalked leaves (to 3 1/2" long) with toothed margins are glossy dark green. Fall color is yellowish brown.

This species is included on the IUCN Red List of Threatened Species. Although this tree is well established in arboretums and botanical gardens throughout the world, it only grows in the wild in several very small populations circling Nanking, China, some of those populations being protected and some still vulnerable to loss from habitat degradation.

Genus name comes from sino meaning Chinese and "jackia" which honors John George Jack (1861-1949) of the Arnold Arboretum.

Specific epithet comes from the Greek words xylo meaning wood and carpos meaning fruit in reference to the woody fruits (drupes) produced by this tree after flowering.

Problems

No serious insect or disease problems.

Garden Uses

Ornamental flowering tree. Lawn specimen. May be difficult to find in commerce.