Hophornbeam, Knowlton
Ostrya knowltonii
Betulaceae - Birch

Description

Leaves: Alternate; simple; oblong-ovate; 1" to 2" long; deciduous; 5-8 pairs of veins; sharply, doubly serrate margin; acuminate apex; thin; tough; dark green above; paler and somewhat hairy beneath; yellow fall color; petiole short, hairy.

Twigs/buds: Twigs slender; red-brown to dark brown. No terminal bud; lateral buds pointed, scales with green bases and brown tips.

Flowers/fruit: Monoecious. Fruit a small nutlet; enclosed in an oval, flattened, papery sac; sacs arranged in cone-like clusters, with the appearance of hops.

Bark: Thin; gray-brown; with small, shreddy plates.

Wood: Extremely hard, so often called "ironwood"; resembles hickory; diffuse-porous; little used.

General: Native to southeastern Utah, northern Arizona, southeastern New Mexico, and west Texas. Slow growing, small tree. Uncommon and found in canyons. Shade tolerant.

Landscape Use: Essentially unknown in cultivated landscapes. No cultivars available and may be difficult to find in any nursery, but could be grown from seed or dug from public land with a permit. Might be a possibility for "native" landscapes. Zones 6(5?)-9.

Characteristics

General

Family Betulaceae - Birch
Cultivar Availability No
Hardiness Zone 6-9
Type Broadleaf
Utah Native Yes

Growth

Growth Rate Low
Mature Height Medium
Longevity High
Is Good Under Power Lines No
Crown Shapes Irregular

Ornamental

Bark No
Fall Color No
Flowers Yes
Foliage Yes
Fruit Yes

Tolerance

Shade High
Salt Medium
Drought High
Poor Drainage Low
Alkalinity High
Transplanting Medium