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.
Allium — the short answer
Allium: grown in zones 4–8, full sun, pH 4.5–7.5.
- USDA zones
- 4–8
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Soil pH
- 4.5–7.5
- FAO ECOCROP
- Sun
- Full Sun
- Growable Ground Plant Database
- Frost-kill temperature
- 23°F
- FAO ECOCROP
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — each tile names its own row's source, because per-field provenance varies.
Score Allium on your exact land.
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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
FAO ECOCROP
Sun
Full Sun
Growable Ground plant catalog
Drainage
well (dry spells)
Growable Ground plant catalog
Frost Kill Temperature
23°F
Where cold starts killing growing tissue. Not a winter-survival floor — a dormant perennial takes far colder, which its hardiness zone answers.
FAO ECOCROP
Minimum Growing Temperature
42.8°F
Below this it stops growing rather than dies — a pace limit, not a survival limit.
FAO ECOCROP
Mature Height
3 ft
Growable Ground plant catalog
Frost-Free Days
120+
The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.
Growable Ground plant catalog
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 (FAO ECOCROP). 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.
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.
A USDA zone is a 10°F band of average annual extreme winter minimum, so zones 4–8 spans average winter lows from -30°F to 20°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 25 outright and splits 26 more down the middle — and which side of that line your land sits on changes the answer.
Zones 4–8·Where Allium growsOpen map →
Where Allium stands, state by state
Allium is rated for zones 4–8 — a cold floor USDA puts at -30 to -20°F. Across the 50 states and DC, 25 sit fully inside that band, the line runs through 26 more, and 0 sit outside it — and inside every split state, the same line runs on at county grain.
Fully inside zones 4–8
25 states
3 of 25 shown
State zone extents: USDA Plant Hardiness Zone Map (PHZM) 2023. A zone is a 10°F band of average annual extreme minimum temperature, so a state that splits the band contains the boundary — its own page draws the county line, and a parcel report resolves which side your land sits on.
What grows around Allium
Growing guides for allium
In rotation planning, allium counts as a Allium — beds recover best when allium crops don’t follow each other in the same spot year over year. (Growable Ground derivation — crop-rotation group from botanical family)
Related plants in perennial flower
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.)
Your land is one point inside Allium's range
This page resolves to the species. Your state page draws the county line, and a report reads the parcel — the soil pH, drainage, sun, and frost dates on your exact ground, which no species average can see.
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.
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How we know this about Allium
The figures above are cited per row, not per site: the pH band names this plant’s own source column, the three temperature figures each carry their own, and days-to-maturity cites the publication that actually lists it. All of it comes from the Growable Ground Plant Database — a compilation over FAO ECOCROP, USDA PLANTS, and university Extension sources, published openly with per-field provenance.
Grounded inUSDA PLANTS Database•USDA PHZM•ASPCA
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 (FAO ECOCROP). 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. (Source: Xerces Society.)
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. (Source: ASPCA.)