Given proper care, royal poinciana (Delonix regia), also known as flamboyant tree, peacock flower and flame tree, celebrates late spring with color. Flame-red clusters of 5-inch blooms drench the gray-barked branches before their foliage unfurls. Fernlike leaves soon follow, and the show continues through midsummer. Long, ornamental seedpods replace blooms by season's end. The tree reaches 30 to 40 feet tall and spreads 50 or more feet, with its branches forming an umbrella of filtered shade. Hardy in U.S. Department of Agriculture plant hardiness zones 10 through 12, royal poinciana has no serious disease, insect or other problems when its basic care needs are met.
Remove nearby vegetation that prevents your royal poinciana tree from receiving full-sun exposure. The tree needs a minimum of six to eight hours of direct, full sunlight each day to reach its full potential. Full-sun exposure enhances flowering and improves the canopy's fullness.
Water a young or recently planted royal poinciana tree's soil regularly. Keep the well-drained soil evenly moist, never soggy, until the tree's roots become established. Native to dry, tropical forests, the drought-tolerant tree needs little more than natural rainfall when mature. Provide supplemental water, if necessary, during the growing season, and reduce water during the tree's winter dormancy.
Prune the royal poinciana to remove low-hanging limbs and promote strong, healthy branches. The tree grows rapidly -- up to 5 feet per year, and weak branches break easily. Use sharp bypass pruning shears for small branches and a sharp pruning saw for larger branches. Sterilize the blades with household disinfectant before and after pruning the tree to prevent the spread of plant diseases.
Fertilize the royal poinciana four to six weeks after planting it and two to three times per year during its first three years, making the additional applications in early spring and fall. After that, nearby lawn fertilizer or a light, annual compost layer suffices. Broadcast a low-phosphorus, controlled-release, granular, 15-5-15 fertilizer, or a fertilizer with a similar ratio, at a rate of 1 pound of nitrogen per 1,000 square feet of soil surface. For slow-release 15-5-15, that translates to roughly 7 pounds of fertilizer per 1,000 square feet. Water the fertilized area until the fertilizer and soil are thoroughly wet. Water helps fertilizer make good soil contact and begin to work.
Rake the area underneath royal poinciana regularly to clean up broken twigs and seedpods. Winds frequently send weak twigs to the ground. The tree's sculptured surface roots tolerate very little competition, and so the ground stays bare except for tree litter and occasional sprouting seedlings.