1281 Ptelea trifoliataCommon Names: common hoptree,hoptree,wafer-ash,stinking ash Family: Rutaceae (citrus Family)
Hoptree is a small tree or large shrub, often low growing and spreading. It gets 15-20 ft (5-6 m) tall with a broad and rounded crown that may spread 10-15 ft (3-5 m) across. The deciduous leaves are compound with (usually) three leaflets, each leaflet around 2-4 in (5-10 cm) long with the middle one the largest. Crushed foliage has a pungent and not particularly pleasant lemony smell. Leaves turn yellow before dropping in fall.
Hoptrees are sometimes dioecious, sometimes monoecious. They produce rounded clusters (corymbs) of stinky little greenish white flowers in late spring. The fruit is a yellowish brown wafer-like samara that is round, thin and flat, about an inch (2.5 cm) in diameter, and edged with a broad papery wing. They hang in conspicuous dangling clusters and typically persist through much of the winter.
The cultivar, “Aurea’ has leaves that start out yellow, turn dark green in summer, then bright yellow again in fall. ‘Glauca’ has bluish green leaves.
Ptelea trifoliata occurs sporadically in eastern North America from southern Ontario to central Florida and west to Illinois and northern Mexico, with scattered and isolated populations further west. It is largely absent from higher elevations in the Appalachian region, although it occurs up to 8500 ft (2590 m) above sea level in the West. Hoptree grows on dry, rocky soils, often on slopes and the edges of forests. This is a subcanopy tree, characteristically associated with sassafras (Sassafras albidum), dogwood (Cornus florida), various hawthorns (genus Crataegus), and eastern redcedar (Juniperus virginiana). Hoptree is the northernmost member of the citrus family in the New World.
Light: Hopee is quite tolerant of shade, even heavy shade, but also does well in full sun. Moisture: Hoptree does best in well drained soils and can handle moderate periods of drought. Hardiness: USDA Zones 4 - 9 . Propagation: Propagate hoptree with greenwood cuttings taken in early summer, or by sowing seed in autumn or spring. Germination is slow and pre-chilling the seeds for 3-4 months improves germination rates. It’s probably best to sow seeds in containers outside in fall, and be patient.
Although a short-lived and slow growing little tree, hoptree is nevertheless an interesting addition to a native plant lawnscape. The foliage is bright and shiny and the long lasting golden brown seed clusters are conspicuous and attractive. Use hoptree as a specimen, in a mixed shrub border, or in a naturalistic woodland garden. It does better in shade than almost any other flowering shrub.
The seeds are bitter and were occasionally used as a substitute for hops in brewing beer. Other parts, especially the bark of the roots, were used medicinally by Native Americans for all manner of ailments, the belief, perhaps, that if it tastes bad, it must be g ood for you. A concoction from the bitter leaves was applied to arrow tips to kill large game.
The flowers smell like a dead animal and are pollinated by carrion flies. Importantly, this member of the citrus family is a host plant for the caterpillars of the giant swallowtail butterfly.
If it weren’t for hoptree, Yankees might never see a giant swallowtail butterfly.
Steve Christman 2/24/17; updated 3/2/17