Clethra is a perennial grown for its white blooms, which open in summer and return year after year. It's hardy across USDA zones 5 through 11. Its summer flowers are a real draw for honeybees, native bees, and butterflies.
Zones
5-11
pH Range
4.5-7
Sun
Part Sun
Days to Maturity
---
Score Clethra on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether clethra actually takes — and those shift from one yard to the next. Enter your address and we'll score clethra against your land's real conditions.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
What Clethra is
Clethra grows as a perennial and reaches around eight feet at maturity. It blooms white in summer.
How to grow Clethra
Clethra grows in USDA zones 5 through 11. Clethra does best in part sun — at least 4 hours of direct sun a day — and soil from pH 4.5 to 7. It needs a growing season of at least 150 frost-free days and about 500 hours of winter chill, which is why climate matters as much as soil.
USDA Zones
5-11
USDA PHZM 2023
Soil pH
4.5 - 7
USDA PLANTS Database
Sun
Part Sun
plant_species_v5.csv
Drainage
Data pending
plant_species_v5.csv
Frost Tolerance
-23°F
plant_species_v5.csv
Mature Height
8 ft
plant_species_v5.csv
Chill Hours
500+
plant_species_v5.csv
Frost-Free Days
150+
plant_species_v5.csv
Start the season right
Plant clethra in part sun with at least 4 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Clethra prefers pH 4.5 to 7 (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. Match watering to the plant's drainage preference and your local rainfall.
Harvest at its peak
Cut clethra blooms in the cool of the morning, just as they open, for the longest display.
Good to know
Good news for pet owners — clethra isn't known to be toxic to dogs or cats. (Source: ASPCA.)
Clethra is a standout pollinator plant — high value to bees and other pollinators. (Source: Xerces Society, Pollinator Partnership.)
Where Clethra thrives
Clethra is hardy across USDA zones 5 through 11. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
Zones 5–11·Where Clethra growsOpen map →
On USDA hardiness-zone overlap, Clethra can grow in these states:
See if Clethra will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether clethra 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.
25+ data sources analyzed in seconds
Frequently Asked Questions
Can I grow Clethra in my zone?
Clethra grows in USDA hardiness zones 5 through 11 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
When should you plant Clethra?
Most growers plant clethra after the last spring frost, once the soil has warmed, leaving enough of the season for its 150-day frost-free need. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Clethra need?
Clethra 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 Clethra need?
Clethra prefers soil pH 4.5 to 7 (USDA PLANTS Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Clethra attract pollinators?
Yes — clethra's flowers are a strong nectar and pollen source for honeybees, native bees, and butterflies (Xerces Society, Pollinator Partnership).
Is Clethra safe for pets?
Clethra is not known to be toxic to dogs or cats based on available data (ASPCA). Always supervise pets around new plantings.