Culture
Best grown in rich, medium moisture, well-drained soils in full sun. Tolerates part shade. Winter hardy to USDA Zones 6-7, but may survive winters in Zone 5 if sited in a protected location. Established trees have drought tolerance.
Noteworthy Characteristics
Poliothyrsis sinensis, commonly called Chinese pearlbloom, is a small deciduous tree that typically matures over time to 30-40’ tall and to 15-25’ wide. It is the sole species contained in the genus Poliothyrsis. It is native to evergreen and deciduous broad-leaved mixed forests plus deciduous forests on mountain slopes in eastern and central China. It was first discovered growing in China by Augustine Henry in the late 1800’s. Legendary plant collector E. H. Wilson first introduced this tree to U.S. gardens by bringing seed from China to the Arnold Arboretum in 1908. This tree bears some resemblance to tree lilac (Syringa reticulate).
Smooth-margined, cordate leaves (each to 7” long) emerge burgundy-bronze in spring, mature to emerald green and finally turn an attractive yellow in fall.
Tiny, fragrant, apetalous, white-aging-to-creamy-buff flowers bloom on many-branched conical panicles to 8” long at the tips of new stems in late August-September. Flowers are monoecious. Flower buds only open slightly (barely see the insides), with each small flower retaining the rounded pearl-shaped appearance of the bud as described by the common name of pearlbloom. Fruits are downy capsules, each containing numerous seeds. Gray bark develops interesting furrows with age.
This tree is particularly noted for its fragrant flowers, late summer flowering period, and attractive foliage.
Genus name comes from the Greek words polios meaning gray and thrysos meaning a panicle in reference to the whitish panicles of this tree.
Specific epithet means of China in reference to the native habit of this tree.
Problems
No serious insect or disease problems.
Uses
Site in locations where buds, flowers and foliage are easily observable.