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Pterostyrax spp.
Epaulette tree
Overview
Pterostyrax spp. is a genus of about four deciduous trees and large shrubs in the storax family (Styracaceae), native to eastern Asia. In gardens the genus reaches 20-40 feet (6-12 m) tall and 15-30 feet (4.5-9 m) wide, forming a rounded to broadly spreading crown on one or several trunks. The leaves are alternate, oblong to oval, 3-8 inches (8-20 cm) long, with finely toothed margins, mid-green above and grey-green beneath. In late spring to early summer the branch tips carry drooping panicles 4-9 inches (10-23 cm) long packed with small white bell-shaped flowers, fragrant in P. hispida. The flowers are followed by narrow, ribbed, bristly or winged fruits about 0.4-0.6 inch (1-1.5 cm) long that hang in clusters into autumn. Bark is grey-brown and smooth, becoming shallowly furrowed with age. Growth is moderately fast where soil is moist and deep. The genus needs ample room for its wide-spreading low branches and tends toward a multi-stemmed, coarse-branched form unless trained to a single leader; flowering is sparse in heavy shade.
Native Range
Native to eastern Asia, with species in China, Japan, and Myanmar. They grow in moist mountain woodlands, streamsides, and forest margins on deep, fertile soils, generally below 6,500 feet (2,000 m).Suggested Uses
Grown as a specimen or in shrub borders and woodland-edge plantings where the drooping flower panicles can be seen from below, spaced 15-20 feet (4.5-6 m) apart. The wide, low habit suits open lawns and large gardens rather than confined spaces. It associates with rhododendrons and other acid-soil woodland shrubs.How to Identify
Appearance
Size & Dimensions
Height20' - 40'
Width/Spread15' - 30'
Reaches mature size in approximately 15 years
Bloom Information
Detailed Descriptions
Foliage Description
mid-green, grey-green beneathGrowing Conditions
Sun Requirements
Requires 5-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grows in full sun to part shade in deep, moist, well-drained, slightly acidic to neutral soil with a pH from 5.5 to 7.0. Regular moisture during the first few years supports establishment; mature trees tolerate brief dry spells but grow and flower less in dry ground. Sheltered positions limit damage to the soft early growth from late frosts and strong wind. Little feeding is needed in reasonable soil. The wood is somewhat brittle, and wide low branches can split under snow load or their own weight. Pests and diseases are few.Pruning
Pruning to a single leader or a few main stems when young builds a stronger, more tree-like framework. Dead, crossing, or low branches are removed in winter while dormant, or just after flowering to keep the next seasons display. Watersprouts and basal suckers can be cut away as they appear.Pruning Schedule
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summerwinter