The Black locust tree, (Robinia pseudoacacia) is also known as False acacia, or Yellow Locust. It has a shallow, aggressive root system that often causes this tree to spread throughout your yard. The Black Locust is a tree that you will either love or hate growing in your yard. Some Black Locust varieties have thorns that are sharp enough to puncture a tire, while others are thornless. The foliage is an interesting aspect of this tree though. The leaves are innately compound and each leaf stem can have between 7 and 19 leaflets growing on it. The leaves act like those on a prayer plant. They fold up and droop when the sun starts to set.
The lumber of the Black Locust tree is used to make furniture. It also provides a home for woodpeckers and other birds. During May or June, when the tree produces clusters of sweetly scented white flowers it draws bees and hummingbirds to feed on the nectar as they help in pollination. Later in the season, seed pods that are 2 to 4 inches in length form and the black seeds inside the seed pods are a source of food for wild animals like squirrels, turkeys, and deer. The Black Locust is hardy in the U.S. Department of Agriculture zones 5 through 9. The can attain heights of 30 or more feet and will grow in most soils with a pH level of 6.1 to 7.8.
Harvest the Black Locust seed pods from off the ground in September to October. The seeds are mature when the seed pods are dry and they turn dark brown.
Remove the seeds from the seed pods holding over a bucket or tray lined with paper towels. You can squeeze the pods open or rip them open with your fingers. If you think of them as a pea pod, you won’t have any trouble. 0nce the pods are open, the seeds will fall out into your container.
Direct sow the seed outdoors in the fall when the seeds are mature. The seed does not store well, so sow in prepared garden as soon as you can.
Prepare a temporary planting site for your Black Locust tree or trees by pulling all the weeds in the area. The temporary garden should have the full sun exposure. You can use any area you like, but perhaps an unused portion of your garden or yard where you can watch them will work the best.
Dig up the soil in a temporary garden area where your seeds are going to be planted. Amend the soil with compost if it is really poor. If your soil does not drain wall, add compost and sand to the temporary garden site.
Seed Preparation and Planting
Nick the seed coat with a small jack knife to aid in germination. Don’t cut too deep that you damage the embryo inside or the seed may not germinate.
Place one seed on top of the soil, spacing the seeds 6 to 12 inches apart. Push the seed into the soil so it is 1/4 to 1/2 inch deep. Cover the seed with soil, firming the soil over the top with your hands so the seed coat is in contact with the soil.
Water the soil until it is evenly moist, but not soggy. .
When the seeds germinate and the trees are 6 to 8 inches tall, transplant them into their permanent locations.