The flame tree (Delonix regia) is a fast-growing evergreen tree that features an abundance of scarlet blossoms. It is a favorite in many tropical and subtropical locations; however, it requires a large space away from buildings so its expansive roots can thrive. It is also known as royal poinciana, named after enslaver Phillippe de Longvilliers de Poincy, but the preferred common name is flame tree due to its appearance when it's in bloom.
The foliage on this species is a bipinnately compound, meaning that each leaf consists of up to 25 pairs of leaflets, and each of those leaflets is further divided into up to 25 more pairs of leaflets. This tree is renowned worldwide for its clusters of exquisite red flowers that blanket the tree and show up in the summer months during warm weather. Each of the five petals is reddish-orange or scarlet color. One petal is bigger than the others and has yellow and white markings. The fruit is a seed pod that can be over a foot long, and the seeds can be germinated and seedlings planted at any time.
|Botanical Name||Delonix regia|
|Common Name||Royal poinciana, peacock flower, gold mohair, royal flame tree, Arbol de Fuego, Gulmohar, flame tree|
|Plant Type||Flowering tree|
|Mature Size||20–40 ft. tall|
|Soil Type||Well-drained clay, loamy, sandy, or gravelly|
|Flower Color||Red, orange|
|Hardiness Zones||10–12 (USDA)|
|Toxicity||Toxic to dogs and cats|
Flame Tree Care
Plant a flame tree in a location where it has enough space to grow. Not only can this variety of tree 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 flame tree is known.
A flame 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 regularly 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 flame 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 in parts of Florida, Texas, and Hawaii, 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.
It's important to prune flame 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.
Propagating Flame Trees
Seed germination and cuttings are used to propagate this tree. Seeds will need to be scarificed first to break open the seed coat and allow water to germinate the seed (see techniques below). It can take more than five years for a newly planted tree to bloom for the first time.
How to Grow Flame Trees From Seed
If you already have a flame tree, harvest the long, strappy dark brown seed pods when they fall to the ground in the spring. With a few extra steps, you can grow the tree from seed.
- Remove the seeds from the pod.
- Soften the coating of the seeds by soaking them in warm water for a day or two before planting in potting mix. Another way to soften seeds is to place them in boiling water and slowly add cold water to drop the temperature to hot but not scalding, then soak for 24 hours.
- Once softened, scarify the seeds by gently nicking or scratching each one with a knife; this process allows water in and speeds up the germination process. Some gardeners suggest rubbing the seed with sandpaper for a few seconds to generate peeling.
- Add well-draining potting mix to a 3- to 6-inch deep seed tray.
- Place each seed 1 inch deep and 3 inches apart.
- Pat the soil firm around each seed.
- Put the tray in a warm, partially shaded outdoor area.
- Keep the soil moist but not overwatered.
- Seeds begin to germinate in four to six days.
- Transplant 8-inch high seedlings to a 1-gallon container.
- Continue transplanting your seedlings as they grow until you are ready to select a site in your landscape to root the tree.
The flame tree can't tolerate frost as it will rot the roots. If there is ever the danger of frost in the typically no-frost zones of 10 to 12 (USDA), cover smaller trees with burlap or a tarp, or add a heating source, such as a light, for extra warmth.
Although flame 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.