The royal poinciana tree (Delonix regia) is native to the island of Madagascar and is one of the most colorful trees in the world. In spring this tree becomes covered with stunning scarlet blooms that last well into summer. Royal poincianas grow from 35 to 40 feet tall and up to 60 feet wide. Hardy in USDA Zones 10 to 12, they cannot tolerate temperatures below 45 degrees Fahrenheit. If you are lucky enough to live in either of these zones, you'll be pleased with this beautiful, flamboyant addition to your yard.
Choose an area of your yard that receives at least six hours of full sun each day and is protected from strong winds. Royal poincianas do best in well-drained soil, so make sure that the location you choose does not have standing water after rain showers. Avoid planting close to building foundations and sidewalks, as the royal poinciana has very shallow roots that may cause damage as the tree matures.
Dig a hole that is double the width and the same height as the container that the royal poinciana tree is growing in. Add 3 inches of organic compost to the hole. Gently squeeze the sides of the planting container until the root ball begins to slide free. Place the tree in the hole, making sure the roots are not compacted. Refill the hole with the loosened soil and tamp down well.
Water until the soil is thoroughly moistened and cover the area around the tree with a 2-inch layer of mulch. Do not let the mulch touch the trunk of the tree. This will help the tree retain moisture during the hot summer months.
Continue to water regularly during the growing season, whenever there is less than 1 inch of rainfall per week. Reduce watering gradually in late fall and stop completely during the winter months.
Add a fresh, 2-inch layer of mulch in late fall to help protect the roots and seal in moisture during winter.
Prune royal poinciana marginally in spring during its first two to three growing seasons to encourage a more attractive, uniform shape. You can prune this tree harder as it grows.