Flower profile

Great rhododendron

Rhododendron maximum

Great rhododendron (Rhododendron maximum) is a shrub or small tree in the Ericaceae family, native in the lower 48 states, blooming mostly June–July across the U.S.

★ Official state flower of West Virginia (1903)Native in the lower 48

Great rhododendron is a flowering plant that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 5 states, and across the U.S. it's most often seen in bloom in June–July.

20states where USDA records it

5Bloomipedia state lists include it

17,928U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Kentucky, North Carolina, Pennsylvania, Tennessee, West Virginia

🏅

West Virginia's official state flower since 1903. Visit the West Virginia page → ^{W. Va. House Joint Resolution No. 19 (Jan. 29, 1903)} West Virginia's flower was chosen by a vote of schoolchildren and adopted by joint resolution rather than written into the state code.

Quick look

Rhododendron maximum is a species of Rhododendron native to the Appalachians of eastern North America, from Alabama north to coastal Nova Scotia. Its common names include great laurel, great rhododendron, rosebay rhododendron, American rhododendron and big rhododendron.
From Wikipedia's article Rhododendron maximum, CC BY-SA 4.0.

It belongs to the Ericaceae family. ^iNaturalist
USDA PLANTS describes it as a shrub / a tree with a perennial life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as native in the lower 48 states and records it in 20 states. ^{USDA PLANTS}
NatureServe lists it as native to North Carolina, Pennsylvania, Tennessee, West Virginia and Kentucky. ^NatureServe
In North Carolina, most iNaturalist sightings of it in flower come in June–July. ^iNaturalist
In Pennsylvania, most iNaturalist sightings of it in flower come in June–July. ^iNaturalist
USDA PLANTS lists its flower color as red. ^{USDA PLANTS}
USDA PLANTS gives its bloom period as mid spring. ^{USDA PLANTS}
USDA PLANTS lists a mature height of about 25 ft. ^{USDA PLANTS}
iNaturalist has 4,953 research-grade sightings of it in North Carolina, ranking #21 among the 192 flowers on our North Carolina list. ^iNaturalist
iNaturalist has 3,109 research-grade sightings of it in Pennsylvania, ranking #66 among the 190 flowers on our Pennsylvania list. ^iNaturalist
iNaturalist has 1,997 research-grade sightings of it in Tennessee, ranking #50 among the 182 flowers on our Tennessee list. ^iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (3,174 records)

Bloom time in the 5 states whose Bloomipedia list includes it

State	Type	Peak bloom	Sightings*
North Carolina	Native	June–July	4,953
Pennsylvania	Native	June–July	3,109
Tennessee	Native	June–July	1,997
West Virginia	Native	June–July	1,824
Kentucky	Native	few records (33)	769

Conservation status

Federal (U.S. ESA)

Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. ^{USFWS ECOS}

NatureServe global

G5 Secure worldwide. ^NatureServe

State rare plant lists

Not listed Not on the official rare plant list in 4 of our 5 states.

See each state

North Carolina: Not listed Not on North Carolina Protected Plant Species List (02 NCAC 48F .0301). NatureServe: S5, secure in North Carolina. ^{02 NCAC 48F .0301}
Pennsylvania: Not listed Not on Pennsylvania classified native plants (17 Pa. Code Ch. 45, Subchapter B, as amended 2023). NatureServe: S5, secure in Pennsylvania. ^{17 Pa. Code Ch. 45}
Tennessee: Not listed Not on Tennessee endangered plants (Tenn. Comp. R. & Regs. 0400-06-02-.04, Rare Plant Protection and Conservation Act). NatureServe: SNR, not yet ranked in Tennessee. ^{TN rule 0400-06-02-.04}
Kentucky: Not listed Not on Kentucky endangered and threatened plant lists (400 KAR 3:040, eff. 2026). NatureServe: S5, secure in Kentucky. ^{400 KAR 3:040}

West Virginia

No list West Virginia has no state law listing endangered or threatened plants (only federally listed species are protected), so we show NatureServe's West Virginia ranks instead. NatureServe: S5, secure in West Virginia.

Rare elsewhere

Other states where NatureServe ranks it rare or missing: MA (S1), ME (S1), NH (S2), VT (S2). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peoplePoisonous to people

NC State Extension lists it as poisonous to humans (severity: low). Poisonous parts: bark, flowers, fruits, leaves, roots, seeds, stems. Symptoms they list: “While the plants are known to contain toxins, ingestion of moderate amounts of azalea (nectar or leaves) poses little toxic hazard.” ^{NC State Extension}

For petsToxic to dogs, cats and horses

ASPCA's entry “Azalea” (Rhododendron spp), which covers the whole genus, lists it as toxic to dogs, cats and horses. Signs include: Vomiting (not in horses), diarrhea, weakness, cardiac… ^ASPCA

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records great rhododendron in 20 states plus Washington, D.C.

AKMEVTNHWAIDMTNDMNILWIMINYRIMAORNVWYSDIAINOHPANJCTCAUTCONEMOKYWVVAMDDEAZNMKSARTNNCSCDCOKLAMSALGAHITXFL

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Connecticut, Delaware, Georgia, Kentucky, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia, West Virginia; District of Columbia.

North Carolina counties with USDA records: Alexander, Ashe, Avery, Buncombe, Burke, Caldwell, Catawba, Cherokee, Clay, Cleveland, Davidson, Davie, Graham, Haywood, Henderson, Iredell, Jackson, Macon, Madison, McDowell, Mitchell, Polk, Rockingham, Rowan, Rutherford, Stokes, Surry, Swain, Transylvania, Watauga, Wilkes, Yancey.

Pennsylvania counties with USDA records: Adams, Allegheny, Armstrong, Beaver, Bedford, Berks, Blair, Bucks, Cambria, Cameron, Carbon, Centre, Chester, Clarion, Clearfield, Clinton, Columbia, Crawford, Cumberland, Dauphin, Elk, Erie, Fayette, Forest, Franklin, Fulton, Greene, Huntingdon, Indiana, Jefferson, Juniata, Lackawanna, Lancaster, Lehigh, Luzerne, Lycoming, Mifflin, Monroe, Montgomery, Montour, Northampton, Northumberland, Perry, Philadelphia, Pike, Schuylkill, Snyder, Somerset, Sullivan, Susquehanna, Union, Venango, Warren, Wayne, Westmoreland, Wyoming, York.

Tennessee counties with USDA records: Anderson, Benton, Blount, Campbell, Carter, Claiborne, Cocke, Cumberland, Fentress, Greene, Grundy, Hamilton, Hancock, Hawkins, Johnson, Knox, Marion, Monroe, Overton, Pickett, Polk, Rhea, Scott, Sequatchie, Sevier, Smith, Unicoi, Union, Van Buren, Washington.

Growing conditions

USDA PLANTS gives Great rhododendron a low shade tolerance, high drought tolerance and medium moisture use. It is rated for soil pH 4.0 to 5.5 and winter lows down to -13 °F.

Shade tolerance: Low
Drought tolerance: High
Moisture use: Medium
Soil textures it is adapted to: coarse, medium
Soil pH range: 4.0 to 5.5
Minimum temperature tolerated: -13 °F
Frost-free days needed (minimum): 150
Annual precipitation range: 36 to 60 inches
Minimum root depth: 18 inches
Salinity tolerance: None
Fertility requirement: Low
Growth rate: Slow
Lifespan: Long
Active growth period: Spring and Summer
Fruit or seed: Brown · Spring to Summer
Can be propagated by: bare root, container, cuttings, seed
Commercial availability: Routinely Available

From the USDA PLANTS characteristics data for RHMA4. USDA ratings are general guidance for the species, not a guarantee for your garden.

Names, range and relatives

Native status by region (USDA PLANTS): Canada: Native; Lower 48 states: Native.

Other scientific names (synonyms in USDA PLANTS): Rhododendron ashleyi.

County records: USDA PLANTS lists it in 315 counties across 17 states; the most are in Pennsylvania (57), Virginia (45), West Virginia (38).

Other Rhododendron on Bloomipedia (11): Rhododendrons and azaleas, Labrador tea, Pinxter flower, Pacific rhododendron, Flame azalea, Mock azalea, Rhodora, Mountain azalea, Swamp azalea, Catawba rhododendron.

More from the Ericaceae family (55 on Bloomipedia; most observed first): Ghost pipe, Striped wintergreen, Mountain laurel, Eastern teaberry (wintergreen), Salal, Woodland pinedrops, Pinesap, Trailing arbutus (mayflower).

More North Carolina flowers

Striped wintergreen

Chimaphila maculata

Native

🌼 Blooms in NC: May–June

Mountain laurel

Kalmia latifolia

★ CT state flowerNative

🌼 Blooms in NC: April–June

Ghost pipe

Monotropa uniflora

Native

🌼 Blooms in NC: June–August

Sources

USDA, NRCS. PLANTS Database, profile RHMA4.
iNaturalist, Rhododendron maximum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Rhododendron maximum (lead quoted under CC BY-SA 4.0).
W. Va. House Joint Resolution No. 19 (Jan. 29, 1903): West Virginia state flower.
State rare and invasive plant lists (9):
Show all 9 state lists
- North Carolina: North Carolina Protected Plant Species List (02 NCAC 48F .0301).
- North Carolina: North Carolina Noxious Weed List (02 NCAC 48A .1702) (the list names any non-native Lythrum; we apply it to purple loosestrife (Lythrum salicaria), which isn't native).
- Pennsylvania: Pennsylvania classified native plants (17 Pa. Code Ch. 45, Subchapter B, as amended 2023).
- Pennsylvania: Pennsylvania Noxious Weed List (3 Pa.C.S. § 1519, PA Dept. of Agriculture) (PDA's page spells garlic mustard “Allaria petiolata”; we match it as Alliaria petiolata).
- Tennessee: Tennessee endangered plants (Tenn. Comp. R. & Regs. 0400-06-02-.04, Rare Plant Protection and Conservation Act).
- Tennessee: Tennessee Pest Plant List (Tenn. Comp. R. & Regs. 0080-06-24-.02).
- West Virginia: West Virginia noxious weeds (W. Va. Code R. § 61-14A-5) (the rule abbreviates some names (e.g. “P. cuspidatum”); we expand them to match).
- Kentucky: Kentucky endangered and threatened plant lists (400 KAR 3:040, eff. 2026).
- Kentucky: Kentucky noxious weeds and invasive plants on state rights-of-way (KRS 176.051; species list from the Kentucky Transportation Cabinet).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Rhododendron maximum (global and state ranks).
Edibility and toxicity: NC State Extension; ASPCA.
Photo: Theo Rickert via iNaturalist · CC BY 4.0 · resized.