Description

Leaves: Alternate; both once and twice pinnately compound; once pinnately compound leaves with 15 to 30 nearly stalkless leaflets; deciduous; twice pinnate leaves with 4 to 7 pairs of 6" to 8" long, lateral "branches"; leaflets ovate to ovate-lanceolate, up to 1-1/2" long by 3/4" wide, margins with fine, rounded teeth, leaflet tip pointed or rounded, glabrous; bright green; nice yellow color in fall.

Twigs/buds: Twigs stout to slender; glabrous; glossy; zigzag; native trees having stiff, sometimes branched, brown to red thorns from 3" to 12" long; thornless varieties are more often planted.  No terminal bud; lateral buds small, nearly hidden by bark, 3 or more at each leaf scar.

Flowers/fruit: Flowers dioecious (some are perfect), small, greenish-white or yellow; not showy; appearing after leaves open.  Fruit a flat, strap-shaped legume; green at first, maturing red-brown; twisted; 12" to 18" long; containing 12-14 dark brown, oval seeds; many cultivars do not bear fruit.

Bark: Smooth and gray on younger branches; on older stems becoming gray-brown to nearly black, and broken by vertical furrows into plates or scaly ridges.

Wood: Slightly important where native; sapwood yellow; heartwood red-brown; growth rings conspicuous; ring-porous; rays conspicuous to naked eye; used for veneer and firewood.

General: Native to most of the eastern U.S.  Very hardy and drought resistant; tolerant of salt and high pH.  Often invades old fields where native, with trunks covered with red thorns.  This species does not fix nitrogen.  Shade intolerant. Fruit and/or plant part can be nuisances; use fruitless varieties if possible.  Thorns or spines that can be dangerous; use thornless varieties if possible.

Landscape Use: A good, large landscape tree because of its relative toughness, its adaptability to a variety of sites, and its fine texture and light shade.  Does well even if surrounded by pavement.  However, it is over-planted in Utah and is not trouble-free.  Thyronectria and other cankers entering through bark injuries have become problems elsewhere and eventually may cause trouble here.  Thornless and fruitless cultivars generally are planted.  Zones 3-9.

Cultivars: 'Christie', 'Imperial', 'Moraine', 'Rubylace', 'Shademaster', 'Skyline', 'Spectrum', 'Sunburst', var. inermis.

Characteristics