The royal poinciana is a landscape tree popular for its bright red/orange blooms that cover the tree for months at a time. About 40 feet tall and 60 feet wide at maturity, royal poinciana is a useful shade tree throughout the growing season. This is a fast-growing tree, hardy only in USDA planting zones 10B through 11 and tropical to subtropical climates outside the United States. Seed pods begin to grow in the summer. They can be up to 18 inches long and 2 inches wide. They fall off the tree in the spring, which can be a nuisance.
Plant the royal poinciana with its mature size in mind. It should be at least 40 to 50 feet from any buildings, giving room for the spread, and at least 10 feet from sidewalks and driveways so the roots don't damage them.
Water the tree to keep the soil moist for the first growing season. It should be watered slowly and deeply, encouraging the roots to grow. Once established, the tree is quite drought-resistant but should still be watered once a week during hot and dry seasons.
Apply a general-purpose, slow-release fertilizer each spring. This should be done after growth is noticed the first year and early each spring thereafter. Follow manufacturer's directions on amount to apply as per age and size of the tree.
Spread a 2-inch layer of compost under the spread of the tree early in the summer. This will supply nutrients to the roots and keep the soil from compacting, ensuring well-draining soil.
Prune the tree in March or April. Cut off any dead or damaged branches, along with branches that are rubbing against each other. Royal poinciana will need to be trimmed to keep a clearance under the canopy for foot or vehicular traffic. Prune weak branches of the young tree and leave strong thick branches to develop the frame of the tree. Trim the tree to shape each year for the first four years.