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

Well-suited

2050

Zone 7a

Plotwright

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

Well-suited

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.

✓

Well-suited today and still thriving 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 40 ecoregions — 35 climate-resilient through 2070 · 5 suited today. 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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Blue Mountains forests

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Canadian Aspen forests and parklands

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Central Pacific Northwest coastal forests

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Central Tallgrass prairie

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Central-Southern Cascades Forests

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Colorado Rockies forests

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Cross-Timbers savanna-woodland

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What it needs

Conditions

Light

Part sun / Part shade

Water

Consistent moisture

Spacing

96"

Habit

Large rounded to spreading multi-stemmed broadleaf evergreen shrub

Care tips

•

Site in part shade with morning sun and shaded afternoons; it prefers cool summers and resents hot, dry exposure.

•

Keep the shallow fibrous roots evenly moist with an acidic mulch (pine needles, bark) and never let them dry out — but ensure sharp drainage to avoid root rot.

•

Keep it well away from walnut, butternut, pecan, and hickory; like most rhododendrons it is sensitive to the juglone those roots produce.

Lifecycle

Planting

Plant in part shade in acidic, humusy, organically rich, evenly moist but well-drained soil; acidify soil before planting and as needed thereafter. Site away from strong winter winds and outside the drip line of walnut-family trees (sensitive to juglone). Use raised beds in heavy clay — good drainage is essential and poor drainage leads to root rot.

Transplanting

Move when dormant; the shallow, fibrous root system transplants readily but must never be allowed to dry out. Do not cultivate around plants — mulch with wood chips, bark, or pine needles instead.

Early growth

Keep roots consistently moist (never wet feet) through establishment. Maintain an acidic mulch to retain moisture and stabilize soil temperature; performs best with morning sun and shaded afternoons in cool-summer climates.

Maturity

Matures to a large rounded shrub 6-10 feet tall (rarely to 20) and 8-12 feet wide, flowering mid to late spring in showy terminal trusses. Prefers cool summer temperatures.

Propagation

Propagated by semi-hardwood cuttings, layering, or seed; an important parent of many frost-hardy hybrid rhododendrons.

Pollination

Needs cross-pollination

Insect-pollinated: the funnel-shaped lavender-pink trusses are a nectar source for butterflies (Missouri Botanical Garden PlantFinder) and the Lady Bird Johnson Wildflower Center flags special value to bumble bees.

Plants don't grow alone

Nectar forage

Bee

Common eastern bumblebee (Bombus impatiens)

The Lady Bird Johnson Wildflower Center records special value to bumble bees, which are well-suited to working the deep funnel-shaped flowers.

Nectar forage

Butterfly

Eastern tiger swallowtail (Papilio glaucus)

Missouri Botanical Garden PlantFinder notes the flowers are a nectar source for butterflies; large swallowtails are typical visitors to spring-blooming Appalachian rhododendrons, though the source does not name species.

Shelter / habitat

Bird

Eastern songbirds (multi-species) (multiple species (Passeriformes))

Missouri Botanical Garden PlantFinder notes the shrub provides shelter and nesting sites for birds and wildlife; its dense evergreen thickets offer year-round cover.

For people

Toxic — do not consume

All parts of the plant are highly toxic if ingested (Missouri Botanical Garden PlantFinder). Grown strictly as an ornamental evergreen shrub, not for any human use.

Native range

Native across 9 US states.

AHS heat range

1-9

Native ecoregions

Naturally belongs in 8 ecoregions — its native range crosses a state or province each one spans (not necessarily this exact habitat).

Appalachian mixed mesophytic forests

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Appalachian-Blue Ridge forests

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Atlantic coastal pine barrens

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Mississippi lowland forests

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Northeastern Coastal Forests

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Northeastern Hardwoods

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Piedmont

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Southeast US conifer savannas

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Climate notes

•

Missouri Botanical Garden PlantFinder lists Rhododendron catawbiense for USDA zones 4-8, 6-10 feet tall (rarely to 20) and 8-12 feet wide, in part shade with medium water and lavender-pink bloom April to June; it tolerates close to full shade and prefers cool summer temperatures.

•

The Lady Bird Johnson Wildflower Center documents it native from Virginia to Kentucky south to Georgia and Alabama (AL, GA, KY, MA, NC, SC, TN, VA, WV), in shade on acidic soils, where it forms dense thickets on rocky mountain slopes and ridges.

•

Missouri Botanical Garden PlantFinder cautions that roots must never dry out, that good drainage is essential (no wet feet), that it should not be sited near walnut-family trees (juglone-sensitive), and that all parts are highly toxic if ingested.

In the designer

Growth over time

72-120" tall · 96-144" spread

Mature rounded shrub 6-10 feet tall and 8-12 feet wide with full spring trusses.

Design roles: Structure · Focal point · Border

Seasonal interest

Spring

Summer

Fall

Winter

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

Catawba rhododendron

At a glance

Related products

Why it matters

Cold hardiness

Heat tolerance

Where this plant fits

What it needs

Lifecycle

Pollination

Plants don't grow alone

For people

Native range

Climate notes

In the designer

Seasonal interest

Sources & citations