Bloomipedia
Rhodora (Rhododendron canadense)
Photo: Erik via iNaturalist · CC BY 4.0 · resized

Flower profile

Rhodora

Rhododendron canadense

Rhodora (Rhododendron canadense) is a shrub in the Ericaceae family, native in the lower 48 states, blooming mostly May–June across the U.S.

Native in the lower 48

Rhodora is a flowering plant that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 2 states, and across the U.S. it's most often seen in bloom in May–June.

9states where USDA records it
2Bloomipedia state lists include it
3,989U.S. sightings*

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

On our lists for: Maine, New Hampshire

Quick look

Rhododendron canadense, the rhodora or Canada rosebay, is a deciduous flowering shrub that is native to northeastern North America.

  • It belongs to the Ericaceae family. iNaturalist
  • USDA PLANTS describes it as a shrub with a perennial life cycle. USDA PLANTS
  • USDA PLANTS lists it as native in the lower 48 states and records it in 9 states. USDA PLANTS
  • NatureServe lists it as native to Maine and New Hampshire. NatureServe
  • In Maine, most iNaturalist sightings of it in flower come in May–June. iNaturalist
  • In New Hampshire, most iNaturalist sightings of it in flower come in May–June. iNaturalist
  • USDA PLANTS lists its flower color as purple. USDA PLANTS
  • USDA PLANTS gives its bloom period as mid spring. USDA PLANTS
  • USDA PLANTS lists a mature height of about 18 ft. USDA PLANTS
  • iNaturalist has 1,881 research-grade sightings of it in Maine, ranking #28 among the 160 flowers on our Maine list. iNaturalist
  • iNaturalist has 1,209 research-grade sightings of it in New Hampshire, ranking #39 among the 157 flowers on our New Hampshire list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (985 records)
Bloom time in the 2 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
MaineNativeMay–June1,881
New HampshireNativeMay–June1,209

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
Maine
Not listed Not on Maine Rare Plant List (Maine Natural Areas Program, 2021). E and T are Maine's official endangered and threatened plants (12 M.R.S.); SC and PE are tracking categories. NatureServe: SNR, not yet ranked in Maine. Maine rare plant list
New Hampshire
Not listed Not on New Hampshire Official Rare Plants List (Ncr 312, eff. Jan 1, 2020). NatureServe: SNR, not yet ranked in New Hampshire. NH Ncr 312
Rare elsewhere
Other states where NatureServe ranks it rare or missing: NJ (S1), NY (S2), RI (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 peopleToxic (slight, per USDA)

USDA PLANTS rates its toxicity as “slight.” (USDA's rating covers people and livestock and doesn't say which parts.) NC State Extension has no page for it. USDA PLANTS

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, diarrhea, hypersalivation, weakness, coma, hypotension, CNS depression, cardiovascular collapse and death. Ingestion of a few leaves can cause serious problems. Rhododendron is typically… 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 rhodora in 9 states.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont.

Maine counties with USDA records: Androscoggin, Aroostook, Cumberland, Franklin, Hancock, Kennebec, Knox, Lincoln, Oxford, Penobscot, Piscataquis, Sagadahoc, Somerset, Waldo, Washington, York.

New Hampshire counties with USDA records: Belknap, Carroll, Cheshire, Coos, Grafton, Hillsborough, Merrimack, Rockingham, Strafford, Sullivan.

Growing conditions

USDA PLANTS gives Rhodora a low shade tolerance, low drought tolerance and high moisture use. It is rated for soil pH 4.0 to 5.3 and winter lows down to -23 °F.

Shade tolerance
Low
Drought tolerance
Low
Moisture use
High
Soil textures it is adapted to
coarse, medium
Soil pH range
4.0 to 5.3
Minimum temperature tolerated
-23 °F
Frost-free days needed (minimum)
120
Annual precipitation range
35 to 50 inches
Minimum root depth
16 inches
Salinity tolerance
None
Fertility requirement
Low
Growth rate
Moderate
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 RHCA6. 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; St. Pierre and Miquelon: Native.

Other scientific names (synonyms in USDA PLANTS): Azalea canadensis, Rhodora canadensis.

County records: USDA PLANTS lists it in 73 counties across 8 states; the most are in Maine (16), Massachusetts (12), New York (12).

Other Rhododendron on Bloomipedia (11): Rhododendrons and azaleas, Great rhododendron, Labrador tea, Pinxter flower, Pacific rhododendron, Flame azalea, Mock azalea, 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 Maine flowers

Ghost pipe (Monotropa uniflora)

Ghost pipe

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Sheep laurel (Kalmia angustifolia)

Sheep laurel

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🌼 Blooms in ME: June–July
Eastern teaberry (wintergreen) (Gaultheria procumbens)

Eastern teaberry (wintergreen)

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🌼 Blooms in ME: July–August

Sources