Native & adapted

Royal poinciana

Delonix regia

Also known as Flame tree · Flamboyant · Gulmohar · Flame of the forest · Phượng vĩ

A spreading shade tree that covers itself in scarlet flowers in early summer. It loves Phoenix heat but needs a warm, frost-protected site to survive its first winters.

FloweringShade treeFast growingHeat tolerantFrost tender

Landscape layersUpper canopy

Mature size

20–30 ft tall and 30–40 ft wide

Climate fit

Urban core · USDA 9b–10a

Plant spacing

25–30 ft from other trees; 15 ft from buildings and paving

Frost

Leaves drop near 32°F; young trees die back below about 28°F. Mature trees survive brief dips to the high 20s°F.

Hardiness guidance

USDA 10–11; young trees damaged below about 32°F

Winter chill

None

Typical harvest

Not a food plant.

Before you plant

These conditions determine whether it will thrive.

Soil chemistry

Fast-draining soil; tolerates alkaline ground.

Required microclimate

Placement is part of the growing system.

The warmest spot available, on the south side of a building or in an urban heat island. Frost protection is needed for the first two or three winters.

Cold hardiness

Cover in a hard freeze below 32°F

It has basically no frost tolerance (UF rates it zone 10B), so leaves drop near freezing and young trees die back hard. Cover young trees every frost night; a mature Phoenix tree that dropped every leaf at 27°F resprouted from the trunk months later, so cover big ones too when a hard freeze is coming.

Leaves and wood: damaged below 32°F

Heat tolerance

Shade from late-afternoon sun

Wants full sun, but reflected west sun and bare gravel around it cause heat and sun injury here. Plant it among other greenery and raise the canopy slowly, because the trunk sunscalds easily.

Sources:

edis.ifas.ufl.edu , asu.edu , phoenixtropicals.com

Right plant, right place

Will Royal poinciana grow at your Arizona property?

Surface roots and a very wide canopy. Plant well away from paving, pools and foundations. Usually starts flowering around age three.

Best regional fit: Urban core · USDA 9b–10a.

Light

Sun exposure

Full sun. Flowering is strongest with heat and long days.

Water

Irrigation

Moderate. Deep water every 7 to 10 days in summer; keep winter watering light.

Fruit set

Pollination

Insect and bird pollinated; forms long woody pods.

Harvest

How to use it

Grown for flowers and broad, filtered shade.

Planting & stewardship

How to help Royal poinciana thrive

1
Wrap the trunk and cover the canopy on frost nights while young.
2
Train a high, wide branch structure early; the canopy spreads much wider than tall.
3
Water deeply and widely to discourage surface roots.
4
Rake up pods if they become messy.

Read the horticultural reference ↗