Royal Poinciana (Gulmohar) Tree: How to Grow Delonix regia (2026)
How to grow royal poinciana, known in India as gulmohar and elsewhere as the flame tree (Delonix regia): where it grows in the US, planting, care, pruning, growing from seed, and the root and storm risks to plan for.
Gulmohar, or royal poinciana (Delonix regia), is a fast-growing tropical shade tree with red-orange summer flowers, growing 35–40 feet tall and up to 60 feet wide. In the US it grows outdoors only in USDA zones 10b–11, such as South Florida and Hawaii. Plant it in full sun, in any well-drained soil, at least 10 feet from pavement, because its surface roots can lift sidewalks. Early structural pruning is essential, because the wood is weak.
Royal poinciana (gulmohar) at a glance
| Botanical name | Delonix regia |
| Common names | Royal poinciana, flame tree, flamboyant tree; gulmohar (India) |
| Family / origin | Fabaceae (legumes); native to Madagascar |
| Size | 35–40 ft tall, 40–60 ft wide |
| Growth rate | Fast |
| Hardiness | USDA zones 10b–11; no frost tolerance |
| Sun | Full sun |
| Soil | Clay, sand or loam, acidic or alkaline, as long as it drains |
| Bloom | Late spring to summer; peak May–July in Florida |
| Flowers | Red-orange, occasionally yellow (var. flavida) |
| Leaves | Fern-like; drops leaves in cool or dry seasons |
| Fruit | Woody seed pods, 1–2 ft long |
Source: UF/IFAS Extension fact sheet ST228, Delonix regia.
Where royal poinciana grows in the US
| Area | Can it grow outdoors? |
|---|---|
| South Florida and the Keys (zone 10b–11) | Yes, a classic street and yard tree |
| Hawaii, Puerto Rico, US Virgin Islands | Yes |
| Frost-free coastal Southern California | Yes, in the warmest spots |
| Central Florida (zone 9b–10a) | Risky; frosts damage or kill it |
| Zone 9 and colder | No, except as a container or bonsai specimen |
Choosing a site and planting
Royal poinciana spreads wider than it is tall and forms large surface roots. Plant it at least 10 feet from sidewalks and driveways, and further from your house, pool and septic system. Grass grows poorly in its shade, and its pods and flowers create litter.
Full sun, with room for a 40–60 ft canopy and no overhead power lines.
Late spring or early summer, when rains begin.
Make the hole 2–3 times as wide as the root ball and no deeper.
Keep the top of the root ball level with, or slightly above, the soil.
Water deeply, then add 2–3 inches of mulch, kept a few inches off the trunk.
Care: water, fertilizer and mulch
- Young trees: water deeply 2–3 times a week for the first few months, then weekly through the first year in dry weather.
- Established trees: drought-tolerant; water only in long dry spells.
- Fertilizer: a balanced, slow-release landscape fertilizer in spring and early summer for young trees. Mature trees need little.
- Drainage: avoid soggy sites, where root rot can set in.
- Mulch: keep a mulch ring around the base instead of grass to reduce root competition and mower damage.
Pruning for a strong tree
Royal poinciana's wood is weak and can break in storms. Pruning while the tree is young is the best defense.
- Develop one strong central trunk and keep major limbs well spaced along it.
- Remove branches with narrow, tight angles, which split easily.
- Keep main limbs less than about half the trunk's diameter.
- Raise the lowest major limbs to 8–12 ft for clearance as the tree grows.
- Prune in late winter to early spring, before new growth. Hire a certified arborist for large trees.
- In hurricane areas, thin the crown lightly so wind passes through. Avoid topping, which weakens the tree.
How to grow gulmohar from seed
Gather seeds from dry, brown pods.
Nick each seed with nail clippers or a file, away from the end where it was attached.
Soak in warm water for 24 hours until the seeds swell.
Plant about 1 inch deep in well-drained seed mix, and keep it warm (70–85°F) and evenly moist.
Seedlings usually appear within 1–3 weeks. Pot them up when they have a few sets of leaves, and plant out at 1–2 ft tall.
Cuttings root poorly, so seed is the usual method. Air layering is an option for copying a specific tree.
Royal poinciana flowering
- Season: late spring into summer, peaking around May–July in Florida.
- Triggers: a distinct dry season, followed by warmth and the first rains.
- Age: seedlings often take several years, commonly around 5–10, to flower well.
- Few flowers? Usually too much shade, too much nitrogen fertilizer, or a tree that is still young.
Cautions, pests and problems
-
Broken limbs
Weak wood and narrow branch angles. Prune for structure while young.
-
Lifted pavement
Surface roots. Plant at least 10 ft from hardscape.
-
Litter
Flowers, leaves and large woody pods drop through the year. Avoid planting over pools and patios.
-
Chewed leaves
Caterpillars occasionally feed on the foliage. Usually cosmetic; use Bt if severe.
-
Decline in weak trees
Root fungi can attack stressed trees. Avoid soggy soil and trunk wounds.
-
Cold damage
Frost kills young trees and damages older ones. Protect seedlings when frost threatens.
UF/IFAS lists royal poinciana as "caution: manage to prevent escape" in South Florida, and not a problem species in Central and North Florida. Remove unwanted seedlings near natural areas.
Gulmohar in culture
Royal poinciana is native to Madagascar, where it is now rare in the wild, but it has been planted throughout the tropics for its spectacular color. In India it is the gulmohar, a familiar sight along streets that blooms in the hot months before the monsoon. In the Caribbean it is called flamboyant, and in South Florida its summer bloom is celebrated, most famously in Miami's Coconut Grove.
Royal poinciana FAQs
Is gulmohar the same as royal poinciana?
Where can royal poinciana grow in the US?
How big does a royal poinciana get?
When does royal poinciana bloom?
How long until a royal poinciana flowers?
Do royal poinciana roots damage sidewalks?
Is royal poinciana invasive in Florida?
Can I grow a gulmohar tree in a pot?
More plant guides
Written by the Eduyush team and reviewed in October 2026. Size, zones, roots, wood strength and pests checked against UF/IFAS Extension fact sheet ST228. Invasive status from the UF/IFAS Assessment of Non-Native Plants.
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How often should I water my plants?
The watering frequency depends on the type of plant, soil, and climate. Generally, it's best to water when the top inch of soil feels dry. Ensure thorough watering until excess water drains out from the bottom of the pot.
What type of soil is best for my plants?
Most plants thrive in well-draining, nutrient-rich soil. Use a general-purpose potting mix for houseplants, and amend garden soil with compost to improve texture and fertility. Specific plants may have unique soil requirements, so check individual care guides.
How much sunlight do my plants need?
Light requirements vary widely among plants. Most houseplants prefer bright, indirect light, while succulents and cacti need direct sunlight. Shade-loving plants thrive in low light conditions. Always check the specific light needs for your plants.
When should I fertilize my plants?
Fertilize during the growing season (spring and summer) when plants are actively growing. Use a balanced, water-soluble fertilizer every 4-6 weeks. Reduce or stop fertilizing in fall and winter when growth slows down.
How do I prune my plants, and why is it important?
Pruning helps maintain plant health and shape. Remove dead, damaged, or diseased branches and spent flowers. Use clean, sharp tools to make precise cuts. Pruning encourages new growth and flowering.
What are the signs of overwatering and underwatering?
- Overwatering signs include yellowing leaves, root rot, and moldy soil. Underwatering signs include wilted, dry, or brown leaves. Adjust your watering schedule based on these signs and the plant’s needs.
How can I improve humidity for my indoor plants?
Increase humidity by misting plants regularly, placing a tray of water and pebbles near the plants, or using a humidifier. Grouping plants together also helps create a more humid microenvironment.
What should I do if my plant is infested with pests?
Identify the pest type first (e.g., aphids, spider mites, mealybugs). Remove visible pests by hand or with a strong stream of water. Use insecticidal soap or neem oil as treatments. Isolate the infested plant to prevent spread to other plants.
How do I repot my plants, and when should I do it?
Repot when the plant outgrows its current pot or roots start emerging from drainage holes. Choose a pot one size larger, gently remove the plant, loosen the roots, and place it in the new pot with fresh potting mix. Water thoroughly after repotting.
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