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Wafer-ash

Ptelea trifoliata

Common names:
wafer-ash, hop tree, common hoptree, stinking ash, water-ash

Content Detail

Wafer-ash is a small native tree or large shrub. It produces small fragrant flowers and wafer-like winged seeds, similar to elms. It is a good plant for naturalizing or woodland landscapes. Despite the name, this tree is not a true ash tree and is unaffected by the emerald ash borer. This species is native to the Chicago region according to Swink and Wilhelm’s Plants of the Chicago Region, with updates made according to current research. 

  • Family (English) Citrus, Rue
  • Family (botanic) Rutaceae
  • Tree or plant type Tree, Shrub
  • Foliage Deciduous (seasonally loses leaves)
  • Native locale Chicago area, Illinois, North America
  • Size range Large shrub (more than 8 feet), Compact tree (10-15 feet), Small tree (15-25 feet)
  • Light exposure Full sun (6 hrs direct light daily), Partial sun / shade (4-6 hrs light daily), Full shade (4 hrs or less of light daily)
  • Hardiness zones Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9
  • Soil preference Moist, well-drained soil
  • Tolerances Alkaline soil, clay soil, Occasional drought, Road salt
  • Season of interest mid spring, late spring, early summer, midsummer
  • Flower color and fragrance White
  • Shape or form Irregular, Multi-stemmed, Round
  • Growth rate Moderate

Size & Form: 

Wafer-ash is a small, native, rounded tree or large shrub, growing 15 to 20  feet high and wide. Despite its name, this tree is not an ash tree, and is unaffected by the emerald ash borer.

Native geographic location and habitat: 

Wafer-ash is native to Ontario, New York to Florida, and west into Minnesota. It grows in rich woodlands, forest edges, and thickets, in moist to gravelly places. C-Value: 8

Bark color and texture: 

The mature bark is dark brown with raised lenticels. Young plants have a smooth, reddish-brown bark.

Leaf or needle arrangement, size, shape, and texture: 

The leaves are alternate, compound, trifoliate (three leaflets) and 2 to 6 inches long. The lustrous dark green leaves change to yellow in the fall. The petioles are as long as the leaflets. The crushed leaves have a pleasant aromatic scent.

Flower arrangement, shape, and size: 

The small, 2 to 3 inch clusters (corymbs) of yellow-green, fragrant flowers appear in May to June. They are not particularly showy.

Fruit, cone, nut, and seed descriptions: 

Light brown, circular samaras (winged papery seeds) appear at the tips of branches in late summer. They persist into winter.

Plant care: 

Wafer-ash is adaptable to sun or shade and most soil types, but prefers moist, well-drained soil. The plants have a tendency to sucker.

List of pests, diseases, and tolerances: 

The tree may get leaf spots and rust, but they are not serious problems.

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