Plant a Delonix regia tree in a location where it has enough space to grow. Not only can this variety of trees reach up to 40 feet, but it can also spread to between 40 and 60 feet wide. While the tree can provide a lot of shade, it can also be damaging if not planted in the proper area. Keep the plant away from walls, pavement, or anything else it might spread into, as the tree has shallow roots and can easily cause damage.
Litter will happen if the branches—which are brittle—break or when the seed pods fall to the ground. You can help reduce the chances of the branches breaking if you can provide a spot with protection from winds and prune to form a strong branching structure.
These trees do best in full sunlight, so choose an area that gets at least six full hours a day. Without adequate light, you might not see the showy red-orange flowers for which the Delonix regia is known.
A Delonix regia tree will grow in a variety of soil conditions, as long as there is drainage. Make sure that the soil dries out between waterings. The tree will tolerate clay, loamy, sandy, or gravelly soils. After planting, cover the soil around the tree—leaving some space near the trunk—with a 2-inch layer of mulch.
Water the tree on a regular basis during the spring, summer, and early fall. Keep the soil moist, but never soggy, until the roots become established. During the late fall months, gradually cut down on the water supply before stopping extra watering during the winter months when the tree goes dormant.
Temperature and Humidity
The Delonix regia tree is native to tropical forests, so it does well in warm, humid environments. It cannot tolerate temperatures below 45 degrees Fahrenheit. It’s easily grown outdoors, but in colder states, the tree should be kept in a greenhouse, conservatory, or on a closed porch.
Give the tree a balanced liquid fertilizer for four to six weeks after planting and then two to three times per year for the first three years. Give an additional application in early spring and fall. Water the tree thoroughly after the soil has been fertilized.
Seed germination and cuttings are used to propagate this tree. Seeds will need to be sacrificed first to break open the seed coat and allow water to germinate the seed. It can take more than five years for a newly planted tree to bloom for the first time.
It’s important to prune delonix regia trees to create a strong tree structure, as the limbs are susceptible to breakage in high winds. Around late March or early April, right before spring growth starts, prune any major branches that are half the diameter of the trunk or below 8 to 12 feet from the ground.
Common Pests and Diseases
Although delonix regia trees don’t have a lot of pests, some species of caterpillars may chew away on the leaves. However, it should not defoliate the entire tree. Additionally, spider mites can be an issue, particularly if the tree isn’t in a humid environment. If you spot spider mites, increase the humidity or set the plant outdoors. Scale insects can also be an issue. They’ll appear under the leaves, but can be removed with cotton swabs dipped in alcohol.
Phellinus noxious is a fungus that may cause the roots to rot. Choosing a spot with soil that drains well can help lessen the possibility that this fungus will invade.