Knowlton Hophornbeam

Ostrya knowltonii

Family: Betulaceae or Birch

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.