Allium is grown for its root. It's hardy across USDA zones 4 through 8 and stands up to deer. Its summer flowers are a real draw for honeybees, native bees, and butterflies, even though the root is the prize. As an allium (the onion family), give it a fresh bed each year — away from where its relatives just grew — so the soil-borne pests and diseases of the family never get a foothold.
Zones
4-8
pH Range
4.5-7.5
Sun
Full Sun
Days to Maturity
---
Score Allium on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether allium actually takes — and those shift from one yard to the next. Enter your address and we'll score allium 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
See Allium
What Allium is
Allium reaches around three feet at maturity. It blooms in summer. It's also deer-resistant.
How to grow Allium
Allium grows in USDA zones 4 through 8. Allium does best in full sun — at least 6 hours of direct sun a day — and soil from pH 4.5 to 7.5, on well-drained ground. It needs a growing season of at least 120 frost-free days, which is why climate matters as much as soil.
USDA Zones
4-8
USDA PHZM 2023
Soil pH
4.5 - 7.5
USDA PLANTS Database
Sun
Full Sun
plant_species_v5.csv
Drainage
well (dry spells)
plant_species_v5.csv
Frost Tolerance
42.8°F
plant_species_v5.csv
Mature Height
3 ft
plant_species_v5.csv
Frost-Free Days
120+
plant_species_v5.csv
Sow directly
Sow allium seed straight into the bed — root crops germinate fast and resent transplanting. Give them full sun.
Match the soil
Allium prefers pH 4.5 to 7.5 (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 maturity
Pull while roots are young and tender — sweeter than oversized ones. Local Cooperative Extension guides publish timing tables.
Good to know
One caution for pet owners — allium is toxic to dogs and cats (moderate severity). Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency. (Source: ASPCA.)
Allium is a standout pollinator plant — high value to bees and other pollinators. (Source: Xerces Society, Pollinator Partnership.)
Where Allium thrives
Allium is hardy across USDA zones 4 through 8. 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 4–8·Where Allium growsOpen map →
On USDA hardiness-zone overlap, Allium can grow in these states:
See if Allium will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether allium 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 Allium in my zone?
Allium grows in USDA hardiness zones 4 through 8 (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 Allium?
Most growers plant allium after the last spring frost, once the soil has warmed, leaving enough of the season for its 120-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 Allium need?
Allium needs full sun — a spot that catches at least 6 hours of direct summer sun a day. In more shade it still grows, but usually gives a smaller, later crop. The catch is that a yard rarely gets even light everywhere — a fence, the house, or one tall tree can quietly take those hours. A Growable Ground report reads the real sun-hours across your land, canopy and buildings included, so you can pick the brightest bed before you plant.
What soil does Allium need?
Allium prefers soil pH 4.5 to 7.5, on well-drained ground (USDA PLANTS Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Does Allium attract pollinators?
Yes — allium's flowers are a strong nectar and pollen source for honeybees, native bees, and butterflies (Xerces Society, Pollinator Partnership).
Is Allium safe for pets?
Allium is toxic to pets (dogs,cats) with moderate severity. Keep it out of reach, and call ASPCA Animal Poison Control at (888) 426-4435 in an emergency.