How to Grow a Golden Shower Tree
A magnificent spring-flowering street or park tree for tropical regions, the golden shower tree (Cassia fistula) slowly matures up to 60 feet tall and 60 to 75 feet wide with a rounded silhouette. Native to the Indian subcontinent, it naturally grows in fertile, well-drained soils in a climate that is warm but very dry in winter but then inundated with rains in spring to trigger the flowering. It's named a "shower" tree because its tiny yellow flowers occur in a long pendant cluster, called a raceme, measuring 6 to 30 inches long. Grow golden shower tree outdoors in U.S. Department of Agriculture plant hardiness zones 10 and warmer, where frost doesn't occur.
Plant the golden shower tree where it grows and flowers its best: Choose any fertile soil landscape that basks in at least 10 hours of direct sunlight daily. Avoid any spot where the soil remains soggy after rain. Once established with far-reaching roots, the golden shower tree tolerates considerable drought without ill, according to Margaret Barwick, author of "Tropical and Subtropical Trees."
Lay a 2- to 3-inch bed of organic mulch under the tree over the root zone. The tree's root zone extends from the trunk to 10 or 20 feet beyond the farthest reach of the branch tips. The mulch shades the soil from summer heat, conserves moisture and helps eliminate weeds. Maintain this mulch layer annually, replenishing it as the mulch decomposes.
Water the tree freely during the heat of spring through fall when the plant actively grows with new leaves and stem length. Supplement natural rainfall as needed to keep the soil moist. Droughts during the summer growing season retards growth and may cause premature leaf drop or branch die-back.
Apply a general, well-balanced fertilizer annually according to Barwick. A 10-10-10 formula suffices; follow product label directions to determine the amount of fertilizer to use based on the golden shower tree's size. Scatter the granules evenly over the root zone, allowing them to nestle among the mulch particles. If you have sandy soil, the fertilizer must have micronutrients in the formulation.
Withhold watering or any irrigation in fall and winter months, allowing only natural rain (if any) to moisten the soil. Ideally, the cool winter temperatures and dry soil causes roughly one-half to two-thirds of the leaves to drop away. The more intensive the winter drought, the more profuse the flowering display in spring once irrigation, spring warmth and natural rains increase.
Prune away any dead or damaged branches any time of year. Use a hand pruners and make cuts 1/4 inch to 1/2 inch above a lower branch junction, leaf or dormant bud. A loppers works better on branches larger than 3/4 inch in diameter. If you prune to shape the tree or remove low or awkwardly angled branches, wait until early summer to prune.
Tip
If you want to propagate the tree, allow the dark brown seed pods to fully mature on the tree, sometimes taking as long as 10 to 12 months. As the pods open and the sticky pulp dries, harvest the seeds and soak them in lukewarm water for 24 hours before planting.
Keep an eye out for sprouting seedlings under the tree. The mulch helps deter seed germination, but occasionally some fallen seeds sprout and need removal before they get too large.
Warning
The University of Arizona notes that golden shower tree may grow well in USDA hardiness zone 9, but extensive frost or subfreezing temperatures cause full leaf defoliation, and regrowth must occur in spring before flowering in late spring to early summer.
Related Articles
References
- "Tropical and Subtropical Trees"; Margaret Barwick; 2004
- Learn2Grow: Cassia Fistula
Resources
Writer Bio
Jacob J. Wright became a full-time writer in 2008, with articles appearing on various websites. He has worked professionally at gardens in Colorado, Florida, Minnesota, New York, North Carolina and Pennsylvania. Wright holds a graduate diploma in environmental horticulture from the University of Melbourne, Australia, and a Master of Science in public horticulture from the University of Delaware.
