Though pretty and fast-growing, black locust is weak-wooded, short-lived and generally weedy. It is hardy, deciduous and forms a broad, upright canopy when mature. Some are more shrub-like. Natural populations are believed to have originated from the eastern United States, particularly along the Appalachians and Ozark Mountains, but have spread across much of the United States and up into Canada.
Green to blue-green compound leaves (leaves comprised of many small leaflets) cover its coarse, thorny branches through summer and turn shades of yellow and tan in fall. In spring, it produces pendulous clusters of fragrant, ivory, wisteria-like blossoms. Pink-flowered cultivars are also available. The fruits are dark brown, flattened pods filled with seeds that mature and split open by fall. Its deeply furrowed bark is variable in color and moderately attractive.
Black locust requires full to partial sun and withstands many well-drained soil types. It tolerates difficult sites, infertile soil and self-sows aggressively—factors which help explain its weedy success. The brittle branches of black locust break easily in storms and high wind and damaged trees tend to sucker. (info source: learn2grow.com)
Not available for sale in Wisconsin.
Genus - Robinia
Species - Pseudoacacia
Common name - Black Locust
Pre-Treatment - Not-required
Hardiness zones - 4 - 8
Height - 30'-50' / 9.1m - 15.2m
Spread - 20'-30' / 6.1m - 9.1m
Plant type - Tree
Vegetation type - Deciduous
Exposure - Full Sun
Growth rate - Fast
Soil PH - Acidic, Neutral
Soil type - Clay, laom, Sand, well drained
Water requirements - Drought tolerant, average water
Landscape uses - Shade Trees
Germination rate - 92%
Bloom season - Late Spring, Early Summer
Leaf / Flower color - Green / White, Light Pink, Ivory
|Germination||1. Use a pair of baby nail clippers to pinch off a piece of each Robinia seed's outer seed coat. Don't cut too deep — just enough to allow water to penetrate to the embryo.|
2. Heat water until it is hot to the touch and pour it into a shallow bowl. Place the Robinias seed in the water and let them soak for 48 hours. They should swell during this period. If they don't, cut the seed coats again and repeat the hot water soak.
3. Fill a small nursery pot with sand and set the Robinia seeds on the surface. Cover it with a 1/8-inch layer of moist sand.
4. Place the pot on a heat mat set at 86F (+30C). At sundown, lower the temperature to 68F (+20C). Raise it to 86F (+30C) in the morning. Continue this until the Robinia seeds germinate in 10 days to five weeks. (source: ehow.com)