Common Name: Asian bell tree
Type: Broadleaf evergreen
Family: Bignoniaceae
Native Range: Southern and eastern Asia
Zone: 10 to 12
Height: 25.00 to 30.00 feet
Spread: 15.00 to 25.00 feet
Bloom Time: Seasonal bloomer
Bloom Description: White or yellow
Sun: Full sun to part shade
Water: Medium
Maintenance: Low
Flower: Showy
Leaf: Evergreen
Other: Winter Interest
Culture
Winter hardy to USDA Zones 10-12 where it is best grown in rich, evenly moist, well-drained soils in full sun to part shade. Site in locations protected from strong winds. Intolerant of frost. In temperate climates, plants may be grown in containers as houseplants. Best with a soil based potting mix. Indoor plants prefer bright indirect light (avoid direct full sun) including several hours per day of curtain-filtered sun from east, west or southern windows. Keep container soils consistently moist but not wet. Soils should not be allowed to dry out. Indoor plants perform best with 70-75 degrees F. temperatures during the day and 60-65 degrees F. temperatures at night. This plant tolerates the dry indoor conditions found in many homes, but appreciates regular misting of the foliage. Container plants may be placed on patios or porches in protected positions in semi-shade during summer, but must be brought indoors prior to first fall frost date. Prune as needed to prevent legginess. Propagate by stem cuttings in summer.
Noteworthy Characteristics
Radermachera sinica, commonly called China doll, serpent tree or emerald tree, is a broad-leaved evergreen tree that is native to subtropical mountain areas of southern China and Taiwan. In its native habitat in optimum growing conditions, this tree will grow to as much as 90' tall featuring bipinnate compound leaves (to 30" long) with glossy dark green leaflets (to 2" long) and fragrant, trumpet-shaped, crinkly-petaled, white or yellow flowers (each to 3" long) which bloom in panicles at the leaf axils or branch ends in spring and summer. Flowers are followed by non-showy fruits in slender capsules. In cultivation in frost free climates, this tree usually grows to a much smaller 25-30' tall. In more temperate climates, China doll has become a very popular foliage houseplant (it rarely produces flowers indoors) which often tops out at 4-6' tall.
Synonymous with and formerly known as Stereospermum sinicum.
Genus name honors amateur botanist J. C. M. Radermacher (d. 1983) Dutch resident of Java.
Specific epithet means Chinese.
Problems
No serious insect or disease problems. Watch for aphids and spider mites on indoor plants.
Uses
Where winter hardy, this tree serves as an interesting specimen/accent or small shade tree in protected areas of the landscape. Where not winter hardy, grow as container plant for patios or porches that must be overwintered indoors.