Treatment with concentrated sulfuric acid for 20-50 min is most effective. Seeds can also be nicked, soaked in boiling water for several minutes, or washed in aerated cold water for 2-3 days. Trees sucker readily from roots and also graft easily. Treatment with indole acetic acid improves rooting. The tree responds well to tissue culture and has been mass propagated by this method.
Black locust grows rapidly, especially when young.
Natural variation in numerous traits has often been observed and many cultivators described. Surles et al. Most of the diversity resided within seed sources with low geographic variation. Clonal selection, early pruning, and close spacing have been effective means of producing straight-stemmed black locust in plantations, especially in Eastern Europe. Comprehensive germplasm collections and plantings for provenance tests were begun in 1982 at Mich. State Univ.