Catalpa is one of the few large trees that actually puts on one heck of a flower display in late May. At a distance, it may look like the tree is covered in pure white blossoms, but on closer inspection you will see the spectacular yellow streaks and purple sp ... ots that line the throat. One of the fastest growing plants we carry. Catalpa like full sun and have shown adaptability to almost any site and soil condition, even though it is native to southern Illinois. Once used as fence posts by pioneers because the wood rots very slowly.