Casia Tree

Question from Loren:

Please help me:) I have roughly a 12 Casia tree about 2 years old looks green but rarely flowers and when it does flower very little and very small flowers and then losses it flowers in about 3 weeks. my landscaper fertilizes and still does not help.

Answer from Pat:

In some cases young subtropical trees take a year or two to get established before blooming. However, that is almost always not the case with cassia. A cassia tree also needs deep watering after planting and for a year or two thereafter to become adequately established. Check the irrigation and make sure your tree has been well irrigated. If lack of irrigation is not the root of the problem, I am pretty sure non-flowering arises from the location of the tree. Cassia needs full sun, no shade from other trees and no competition for their roots, for example a lawn too close around the trunk, Algerian ivy close by or a nearby eucalyptus tree within 50 feet. But mostly it needs a warm protected spot, such as to the south of a warm wall, not to the north of it. Reflected heat from a sunny road is good too. A lot of shrubbery or other trees or buildings or fences casting shade is not good.

Most of all a cold wind will not do for cassia. Cold wind off the sea usually prevents blossoming or if not totally prevented, the flowers will soon fall off. I have seen this happen in our town where, despite my advice, a building owner insisted on planting a cassia in a cold spot next to the street on the north of his building in the teeth of the wind a few blocks up a hill from the ocean. That cassia was lovely and in full bloom when it was planted. Immediately all the blossoms fell off. Since then it has grown steadily smaller. It is now scrawny-looking, sparsely foliaged. The bunches of flowers when they occur are much smaller than when it was planted and they fall off quickly. Then no more come. Fertilizer will not help.