Black locusts trees can be readily identified in late spring and early summer by their showy display of perfumed white flowers. After blooming, black locusts produce copious dark seed pods. However, they propagate principally through sending out shoots from their root base. As these trees grow well and multiply quickly, even in nutrient poor and acidic soil, they are used in reforestation efforts. Once mature, they reach between 30 to 50 feet in height. You can propagate black locusts cuttings taken from the roots or use shoots cut from the tree.
Collecting Black Locust Cuttings
Prepare the soil by mixing equal parts of peat moss, sand and perlite. This creates a rich soil with good drainage. Use planting boxes or prepare the soil directly in the ground once overnight frosts have passed in early spring.
In early spring, use the shovel to dig carefully around the root stock of a mature, dormant black locust. When you see the root separate into thinner offshoots, around a half inch in thickness, use the spade to expose the root so that you can cut it easily.
Cut 4- to 5-inch sections from the root. Identify which end grew closest to the tree trunk by leaving it flat, but cut a sharp angle in the distal end, which grew farthest from the trunk. Cover the exposed roots with the removed soil.
Alternatively, use sharp pruning shears to cut 6- to 12-inch cuttings from suckers growing off the black locust. Suckers are offshoots that the tree sends out, either from the trunk or existing branches. As you collect cuttings, cut an angle in the end growing closest to the trunk.
Place your black locust cuttings in dry sand for three weeks.
Black Locust Plantings
In early spring, plant root or wood cuttings into the prepared soil mix, 5 inches apart. Submerge cuttings half way into the soil, planted with the angled end in the dirt and the flat end showing. Water well.
Keep the soil well moistened. Plant outdoors or thin existing plantings when cuttings start to produce shoots and leaves.
As your plantings grow, weed regularly and protect them from predators, such as deer. The emerging thorns are soft until the trunk thickens and hardens as it matures. Once established, black locusts require little attention, except warding off insects.
Watch out for pests, such as black locust borers and leaf miners, as the plantings grow. These insects attack the trunk and leaves. Use the plant insecticide at the first signs of insect damage.