Robinia pseudoacacia ‘Purple Robe’ is a drought-tolerant, black locust tree that reaches heights between 30 and 40 feet. Their twigs can feature pairs of thorns, but they may also be thornless. As it is a tree in the legume family, it helps increase the amount of nitrogen found in the soil around it. This is beneficial for overall soil health. You’ll be able to spot long shoots of fragrant, purple flowers around May, which give way to flat, purple-brown pods of fruit that will persist throughout winter. Their leaves consist of up to 23 thin, bronze-green, oval leaflets with rounded, smooth margins. They start out bronze-red in the springtime and end up with a yellow Autumn color.