Introduction

This cultivar of the deciduous North American native tree reaches 15 feet in height with a spread of 10 to 15 feet and forms a broad, rounded canopy over a slender, grey trunk. The trifoliate, four- to six-inch-long leaves are glaucous blue-green in summer, turning yellow in fall before dropping. Inconspicuous greenish-white flowers appear in terminal clusters in June and July, their presence easily detected by the delicious orange blossom-like perfume. The blooms are followed by interesting, one-inch-diameter, flattened, tan "wafers" which will persist on the tree if not first consumed by wildlife. In the past, this bitter fruit was used as a substitute for hops in brewing beer.

General Information

Scientific name: Ptelea trifoliata

Pronunciation: TEE-lee-uh try-fole-ee-AY-tah

Common name(s): 'Glauca' common hoptree, 'Glauca' wafer-ash

Family: Rutaceae

USDA hardiness zones: 4A through 9A (Figure 2)

Origin: native to North America

Invasive potential: native cultivar

Uses: specimen; deck or patio; container or planter

Description

Height: 5 to 15 feet

Spread: 10 to 15 feet

Crown uniformity: irregular

Crown shape: round, vase

Crown density: moderate

Growth rate: moderate

Texture: medium

Foliage

Leaf arrangement: alternate (Figure 3)

Leaf type: trifoliate, odd-pinnately compound

Leaf margin: entire, serrate

Leaf shape: ovate, elliptic (oval), oblong

Leaf venation: brachidodrome, pinnate

Leaf type and persistence: deciduous

Leaf blade length: 2 to 4 inches

Leaf color: blue or blue-green

Fall color: yellow

Fall characteristic: showy

Flower

Flower color: white/cream/gray

Flower characteristics: not showy

Fruit

Fruit shape: round

Fruit length: 0.5 to 1 inch

Fruit covering: dry or hard

Fruit color: brown

Fruit characteristics: attracts squirrels/mammals; showy; fruit/leaves not a litter problem

Trunk and Branches

Trunk/bark/branches: branches droop; not showy; typically multi-trunked; thorns

Pruning requirement: needed for strong structure

Breakage: resistant

Current year twig color: brown

Current year twig thickness: medium

Wood specific gravity: unknown

Culture

Light requirement: full sun, partial sun or partial shade, shade tolerant

Soil tolerances: clay; sand; loam; acidic; slightly alkaline; well-drained

Drought tolerance: high

Aerosol salt tolerance: unknown

Other

Roots: not a problem

Winter interest: no

Outstanding tree: yes

Ozone sensitivity: unknown

Verticillium wilt susceptibility: unknown

Pest resistance: resistant to pests/diseases

Use and Management

One of a few small trees which performs well in deep shade. Plant it close to the patio or deck or locate it in a shrub border for fragrant flowers and yellow fall color display. Its native habitat is dry, rocky upland sites making it well-suited for non-irrigated landscapes.

Naturally found in the shade along the edges of woods, especially on rocky slopes in the Mississippi Valley, wafer-ash can be planted in full sun to deep shade and prefers well-drained, fertile, moist soil. While plants are better off if not exposed to extremes of wetness or dryness, wafer-ash is drought-tolerant once established. Transplants readily from the field.

Other cultivars include: 'Aurea' with yellow foliage through the spring and into the summer.

Propagation is by budding, layering, or grafting.

Pests and Diseases

No pests or diseases are of major concern although it is occasionally bothered by tree-hoppers, leaf spot, and rust.