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Ptelea spp.
hop tree
Overview
Ptelea is a small genus of deciduous shrubs and small trees in the citrus family (Rutaceae), native to North America, with P. trifoliata, the common hop tree or wafer ash, the most familiar species. Plants grow 6-25 feet (1.8-7.6 m) tall with a rounded, spreading crown and aromatic bark and foliage. The leaves are divided into three glossy leaflets, each 2-5 inches (5-13 cm) long, that give off a citrus-like scent when crushed, reflecting the genus place in the citrus family. Clusters of small greenish-white flowers open in late spring to early summer; they have a strong, somewhat musky scent that draws flies, bees, and other insects. The flowers are followed by flat, rounded, papery winged fruits (samaras) about 0.8 inch (2 cm) across that hang in clusters and persist into winter; their resemblance to wafers gives one common name. The genus tolerates a range of soils, shade, and dry conditions, and is among the more shade-tolerant members of the citrus family. Some people find the flower scent unpleasant at close range.
Native Range
Ptelea is native to North America, with P. trifoliata ranging widely across the eastern and central United States into southern Ontario and parts of Mexico, and other species in the southwest. It grows in open woodland, rocky slopes, thickets, dunes, and woodland edges.Suggested Uses
Grown in native and wildlife gardens, woodland edges, and shrub borders, and as a small specimen tree for shade or screening. The aromatic foliage and persistent winged fruits add interest, and the plant supports swallowtail butterflies. It suits naturalistic and pollinator plantings.How to Identify
Appearance
Size & Dimensions
Height6' - 25'
Width/Spread6' - 20'
Reaches mature size in approximately 8 years
Bloom Information
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-8 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
Grow Ptelea in full sun to part shade in average, well-drained soil; the genus tolerates poor, dry, rocky, and sandy soils once established. It also tolerates more shade than most fruiting trees, making it useful at woodland edges. Water regularly while young, then occasionally, as established plants withstand short drought. Little feeding is needed in reasonable soil. The genus is hardy and has few serious problems, though leaves may show rust or be chewed by caterpillars, including swallowtail larvae that feed on this citrus relative. It self-seeds where conditions suit, and seedlings can be removed if not wanted.Pruning
Ptelea needs little pruning beyond removing dead, damaged, or crossing branches in late winter. It can be grown as a multi-stemmed shrub or trained to a single trunk while young. Light shaping after flowering keeps a tidy rounded form.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
winter
Container Growing
Suitable for container growing
Minimum container size: 10 gallons