Rhododendron is a perennial grown for its blooms, which open in spring and return year after year. Its spring flowers are a moderate draw for honeybees, native bees, and butterflies.
Zones
Data not available
pH Range
4.5-6
Sun
Part Sun
Days to Maturity
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Score Rhododendron on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether rhododendron actually takes — and those shift from one yard to the next. Enter your address and we'll score rhododendron against your land's real conditions.
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What Rhododendron is
Rhododendron grows as a perennial and reaches around ten feet at maturity. It blooms in spring.
How to grow Rhododendron
Rhododendron does best in part sun — at least 4 hours of direct sun a day — and soil from pH 4.5 to 6, on well-drained ground. It needs about 800 hours of winter chill, which is why climate matters as much as soil.
USDA Zones
Data not available
USDA PHZM 2023
Soil pH
4.5 - 6
USDA PLANTS Database
Sun
Part Sun
plant_species_v5.csv
Drainage
well (dry spells)
plant_species_v5.csv
Mature Height
10 ft
plant_species_v5.csv
Chill Hours
800+
plant_species_v5.csv
Frost-Free Days
0+
plant_species_v5.csv
Start the season right
Plant rhododendron in part sun with at least 4 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Rhododendron prefers pH 4.5 to 6 (USDA PLANTS Database). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at its peak
Cut rhododendron blooms in the cool of the morning, just as they open, for the longest display.
Good to know
One caution for pet owners — rhododendron is toxic to dogs and cats and horses (severe severity). Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: ASPCA.)
Rhododendron offers moderate value to bees and other pollinators. (Source: Xerces Society, Pollinator Partnership.)
Where Rhododendron thrives
Whether rhododendron thrives on a given site comes down to its soil pH, drainage, sun, and frost dates — the conditions that vary parcel to parcel.
See if Rhododendron will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether rhododendron actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Frequently Asked Questions
Can I grow Rhododendron in my zone?
Zone data for rhododendron is being finalized. A Growable Ground report checks your parcel's full suitability against federal soil, climate, and zone data.
When should you plant Rhododendron?
Most growers plant rhododendron after the last spring frost, once the soil has warmed. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Rhododendron need?
Rhododendron does well in partial sun — around 4 hours of direct sun, and it takes some afternoon shade in stride. That flexibility makes it a good match for a bed the house or a nearby tree shades for part of the day. A Growable Ground report maps how the sun actually falls on your land, hour by hour, so you can set it where the light lines up.
What soil does Rhododendron need?
Rhododendron prefers soil pH 4.5 to 6, on well-drained ground (USDA PLANTS Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Rhododendron attract pollinators?
Yes — rhododendron's flowers are a solid nectar source for honeybees, native bees, and butterflies (Xerces Society, Pollinator Partnership).
Is Rhododendron safe for pets?
Rhododendron is toxic to pets (dogs,cats,horses) with severe severity. Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency.