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Piedmont azalea
Habit (mature) · Ezra S F / Wikimedia Commons · CC BY 2.0
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Piedmont azalea

Rhododendron austrinum
A tall, erect, multi-stemmed native deciduous azalea of the lower southeastern United States, prized for clouds of intensely fragrant golden-yellow to apricot-orange tubular flowers that open in early to mid spring just as the leaves emerge. One of the more heat- and humidity-tolerant native azaleas, it forms an open, upright shrub 8-10 feet tall that reads as a small flowering tree in maturity. It wants part shade, acidic humus-rich soil, and consistent moisture; like every Rhododendron, all parts are toxic if eaten.
Review: Source-backed
Climate fit: narrow (30/100)
Focal point
Pollinator
Structure
Light
Part shade
Water
Consistent moisture
Mature size
96-120" tall · 54" apart
Hardy in zones
7a-9b
cold to frosty winters
Native in Illinois
No
The long, fragrant, tubular spring flowers are insect- and bird-pollinated; ruby-throated hummingbirds and large swallowtail butterflies work the long corolla tubes, and bumblebees forage the trusses.

Cold hardiness

Future
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).
Marginal
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, but marginally possible by 2050.

Heat tolerance

Future
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...

Sources & citations

Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Piedmont azalea (Rhododendron austrinum). Retrieved 2026, June 13, from https://plotwright.garden/plants/rhododendron-austrinum
Sources for every fact
Every fact on this page traces to a source. 18 fields cited18 source-backed.
NC State Extension Gardener Plant Toolbox
University extension service
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
Growth stages
Lifecycle
Regional guidance
Success tips
Designer notes
Wikimedia Commons
Photo · CC BY 2.0
Backs 1 field
Image

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