Common Hoptree

Ptelea trifoliata L. ssp. trifoliata

Description

Common hoptree  is a member of the rue family (Rutaceae). ¹   It is a small, deciduous tree up to 25 feet in height and trunks usually less than 8 inches in diameter.  The bark is brown and ill-scented.  The alternate, compound leaves are trifoliate with each leaflet sessile and 2-5 inches long. ²    The flowers are small but clustered terminal inflorescences. ²  They are pollinated by carrion flies. ²  Fruits have broad, veined wings that are nearly circular and 1 inch in diameter.

Leaves and flowers of common hoptree.  Maryland Biodiversity Project–J. Brighton ³

Fruits of common hoptree.  Maryland Biodiversity Project, J. Stasz. ³

Distribution

Common hoptree is distributed in the Central and Eastern United States. ⁵  It is widely distributed throughout the Eastern United States, Ontario and Quebec Canada. ⁵  In Maryland common hoptree is distributed along the Potomac River drainage from Allegany to Charles County. ³

Native distribution map of common hoptree.  Virginia Tech Dendrology. ⁴

Wildlife Importance

Hoptree is the larval host to the Eastern Tiger Swallowtail and Giant swallowtail butterflies. ⁵ It also provides food for birds, mammals and nectar for butterflies. ⁵

Economic Importance

Common hoptree is used horticulturally as a hedge species, but has little commercial importance. ⁶ It has several medicinal uses such as a tonic and antibacterial and has a soothing effect on mucus membranes. ⁶

Threats

Common hoptree has limited distribution inCanada where it is listed as a species of special concern. ⁷ It is listed as Critically Imperreled (S1) in New Jersey and New York and Vulnerable (S3) in Maryland. ⁷

Interesting Facts

• Common hoptree has three common names.  Common hoptree is  from the prior use of its seeds as a substitute for hops in making beer. ²  Wafer ash comes from the thin membrane surrounding the  seeds. ²  Stinking ash comes from the pungent bark, foliage and flowers. ²
• It is the northernmost representative of the rue family in North America. ⁵

References

1. North Carolina State Extension–Ptelea trifoliata
2. Missouri Botanical Gardens–Ptelea trifoliata
3. Maryland Biodiversity Project–Ptelea trifoliata var. trifoliata
4. Virginia Tech Denrology–hoptree
5. Lady Bird Johnson Wildflower Center–Ptrelea trifoliata
6. Medicinal Herbs–Hop Tree
7. Government of Canada:  Common hoptree (Ptelea trifoliata): COSEWIC assessment and status report 2015

Contributed by J. Hull

Towson University Glen Arboretum