Ptelea spp.

hop tree

Rutaceae North America

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Fragrant (moderate)Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 4–9

Overview

Ptelea spp. 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 spp. 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

Identify Ptelea spp. by its aromatic, three-part (trifoliate) leaves that smell of citrus when crushed and its clusters of flat, rounded, papery winged fruits. The small greenish-white flowers are strongly scented. The bark is smooth and gray and also aromatic when scratched.

Appearance

Size & Dimensions

Height6' - 25'

Width/Spread6' - 20'

Reaches mature size in approximately 8 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Spring Summer

Flowering occurs in late spring to early summer, roughly May to June, over two to three weeks. The greenish-white flowers are small but numerous and heavily scented. Winged wafer-like fruits follow and remain on the plant into autumn and winter.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

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

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

loam sand rocky clay

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

5-10 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow Ptelea spp. 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 spp. 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

winter