Trees

Question

I planted a casia fistula in February that I raised in a pot. I got it from the wild. It’s now 9 feet from tall. As it grew I trimmed the lower limbs. The bottom limbs are now 4 feet from the ground. I know these can grow from 15 to 30 feet. My question is, can I certail the growth in height and how is it done? I would like to keep the height around 12 to 15 feet. Also, when do the limbs start to grow outward? They range in length, now, from 12 to 18 inches.

Answer 1

Beautiful tree, good choice for your location. I too have a young Casia fistula, but at my home near Bangkok. ‘Golden rain tree’is the national tree and national flower here in Thailand.
I planted mine from a nursery container, also in February or March. Like your tree, mine is in the early, immature stage of growth, putting on height with what’s called “apical dominance”. So its too early to expect branching out and lateral branch development. You can suppress apical dominance and encourage lateral branching by snipping the terminal growth by a few inches. I don’t recommend heading back too heavily or you will get a vigorous reaction of multiple sprouting that will look bushy at the top and create top-heaviness, and require more maintenance.
Keeping the height to 12 – 15 feet is unrealistic without destroying the natural form and beauty of this tree, which commonly grows 30 to 60 feet in height.
I planted mine for the natural beauty of the tree, but also for the height and shade for the western side of our house where the tropical sun beats down in the afternoon.