Robinias reproduce on their own, but you can also help if you want the plant in a specific place. You have two options to ensure success.
The black locust, also known as acacia, is a popular deciduous tree in the garden. Normally you don't need to do anything for the propagation, because the plant does it all by itself with seeds and root suckers. Just to the places where it ends up. But if you want the robinia in a very specific place, you can also propagate it yourself. You can do this using the two options mentioned above.
» But be careful: The black locust belongs to the so-called neophytes. These are plants that have their origins in other, distant regions and show a strong propagation. They tend to spread a lot. Native plants are then often crowded out.
The natural reproduction of black locust
After flowering, pods with seeds are formed. The pods are relatively heavy and usually end up near the mother tree. At first glance, this does not appear to be widespread, but the seeds are germinable for up to 30 years. If the conditions are right - free locations, moisture and sun - a more or less large robinia plantation will quickly develop.
The black locust finds a second way to propagate with its root runners. The root suckers grow in all directions and quickly form new trees. Then other plants are often crowded out.
Propagating robinia seeds
The method is simple and safe. Pick some seed pods in the fall. They are ripe from October when they turn brown. Retrieve the seeds from the pod and keep them cool and dry until spring. Spring is sowing time. The seeds have a thick and waterproof shell. Therefore you have to roughen or scratch the shells with sandpaper or a file. Then put the seeds in a container and scald them very briefly with hot water. The hot water overcomes the so-called "germ inhibition". The seeds are then placed in lukewarm water and have toSwell for a day until doubled in size.
In the next step, place the seeds in seed soil about five millimeters deep. Keep the soil evenly moist and place the pot in a bright, moderately warm spot. The seeds will germinate in about a week. As soon as the seedlings are big enough, i.e. have several leaves, you can separate the plants and put them outside after the last frost.
Propagating robinia via root cuttings
This method also works well. To do this, cut root cuttings in spring or autumn. Root suckers with a thickness of half a centimeter or more are suitable. The sections should be five to ten centimeters long. Then put the root cuttings in pots with potting soil, about so deep that they still stick out a little bit from the ground. Keep the soil slightly moist and place the pots in a warm spot. When the cuttings sprout, water them a little more.
Put spring cuttings outside after the ice saints. Fall cuttings remain indoors until the following spring. They do well in a moderately warm spot and are strong enough to move outdoors in spring.