Cold hardiness

Future

2050

2100

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.

Now

Zone 6b

USDA

Published baseline for this location from 1991-2020.

Source: USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer

Won't grow here

2050

Zone 7a

Plotwright

Projected zone for this same location in 2050 (2041-2070) using SSP3-7.0 (regional rivalry).

Won't grow here

In plain terms: This location is in Zone 6b today. Its hardiness profile is cold winters, and coldest nights are typically around -3°F. By 2050, the projected hardiness zone is Zone 7a based on SSP3-7.0 (regional rivalry). That is a +0.5-zone shift from Zone 6b to Zone 7a by 2050.

✕

Out of range today and still out of range in 2050.

Heat tolerance

Future

2050

2100

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.

Loading AHS heat-zone data for this location...

Where this plant fits

Suitable across 36 ecoregions — 33 climate-resilient through 2070 · 3 newly possible by 2070. Best matches first.

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Arizona Mountains forests

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Atlantic coastal pine barrens

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California coastal sage and chaparral

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Canadian Aspen forests and parklands

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Central Pacific Northwest coastal forests

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Central-Southern Cascades Forests

What it needs

Conditions

Light

Full sun

Water

Moderate water

Spacing

240"

Habit

Deciduous small tree or large shrub with arching, sparsely-thorny branches that carry dramatic terminal sprays of waxy deep-red pea-flowers through the warm season. It is a tough, frost-hardy-to-the-roots subtropical tree — it can resprout after a light freeze (roughly zone 8b and up) and tolerates wet ground. The branches bear scattered thorns, so site it away from paths. The seeds and bark contain toxic erythrina alkaloids and must not be eaten. In its native range the flowers are pollinated by perching birds and hummingbirds, not bees.

Care tips

•

Give it full sun and room for a 15-25 ft spread; the arching crown wants space to show its flowers.

•

At its cold edge, treat it as die-back-and-resprout — cut frosted top growth back hard and let it rebuild from the base.

•

Site it well away from paths and play areas because of the scattered thorns and the toxic seeds and bark.

Lifecycle

Planting

Plant in full sun in spring once frost danger has passed, in any reasonable soil; it tolerates wet ground better than most trees but flowers best with good drainage.

Transplanting

Set out young container trees in spring while they are establishing; give the eventual 15-25 ft spread room and keep it away from paths because of the thorns.

Early growth

Grows quickly once established, sending up arching thorny shoots and often flowering within the first few warm seasons.

Maturity

Reaches 15-25 ft tall and wide as an open, arching small tree; flowers heavily on new wood through the warm season and goes deciduous in cool spells.

Propagation

Propagated from seed (scarify the hard coat first) or from hardwood cuttings; established trees resprout vigorously from the base after a light freeze.

Pollination

Pollination not applicable

In its native range the deep-red flowers are pollinated by perching birds and hummingbirds drawn to the nectar, not by bees — the blossoms are shaped and colored for bird visitors. Where hummingbirds are absent, fruit set is sparse; the tree is grown chiefly for its flowers, which still appear reliably.

For people

Toxic — do not consume

Toxic — the seeds and bark contain erythrina alkaloids and no part of the plant should be eaten. The handsome red seeds are especially hazardous to children. Grow it for ornament only.

Climate notes

•

Hardy in USDA zones 8b-11b; native to subtropical southern South America — southern Brazil, Uruguay, Paraguay and northern Argentina (POWO (Kew); native status in Brazil per Flora e Funga do Brasil).

•

Frost-hardy to the roots: top growth is damaged by hard freezes but the tree resprouts from the base after a light freeze, roughly zone 8b and warmer — treat it as die-back-and-resprout at its cold edge.

•

Unusually tolerant of wet ground for a flowering tree, but needs full sun and warmth to flower well; expect the best bloom in long, hot summers.

•

The branches carry scattered thorns and the seeds and bark are toxic — site it away from paths, play areas, and reach of children.

In the designer

Growth over time

180-300" tall · 180-300" spread

A mature spreading small tree at full 15-25 ft height and width, a seasonal focal point.

Design roles: Focal point · Structure

Seasonal interest

Spring

Summer

Fall

Winter

Filled = the plant has seasonal interest · ▾ now = your current season

Cockspur coral tree

At a glance

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

For people

Climate notes

In the designer

Seasonal interest

Sources & citations