Sweet Alyssum is an annual or perennial grown for its blooms, which open from spring through fall and return year after year. It overwinters in USDA zones 5 through 9 and is grown as a summer annual wherever the season is long enough. Notably, it shrugs off deer and grows just as well in a container as in the ground. Its flowers are a real draw for honeybees, native bees, and butterflies.
Sweet Alyssum — the short answer
Sweet Alyssum: grown in zones 5–9, full sun, pH 6–7, about 55 days to maturity.
- USDA zones
- 5–9
- NC State Extension Gardener Plant Toolbox
- Soil pH
- 6–7
- We haven't confirmed this against a published source yet.
- Sun
- Full Sun
- Converted from Courtesy of University of Wisconsin–Madison Extension
- Days to Maturity
- 55 days
- We haven't confirmed this against a published source yet.
- Frost-kill temp (growing season)
- 25°F
- We haven't confirmed this against a published source yet.
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 Sweet Alyssum on your exact land.
Zone averages can't see the slope, soil, frost, and sun that decide whether sweet alyssum actually takes — and those shift from one yard to the next. Enter your address and we'll score sweet alyssum against your land's real conditions.
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What Sweet Alyssum is
Sweet Alyssum grows as an annual or perennial and reaches around 6 inches at maturity. It blooms from spring through fall. It's also deer-resistant and well suited to containers.
Mature height, bloom period, deer resistance and container suitability: We haven't confirmed this against a published source yet.
How to grow Sweet Alyssum
Sweet Alyssum overwinters in USDA zones 5 through 9 and is grown as a summer annual wherever the season is long enough. Sweet Alyssum does best in full sun — at least 6 hours of direct sun a day — and soil from pH 6 to 7, on well-drained ground. It needs around 600 growing degree days to mature and a growing season of at least 40 frost-free days, which is why climate matters as much as soil.
USDA Zones
5-9
NC State Extension Gardener Plant Toolbox
Soil pH
6 - 7
We haven't confirmed this against a published source yet.
Sun
Full Sun
Converted from Courtesy of University of Wisconsin–Madison Extension
Drainage
well (dry spells)
We haven't confirmed this against a published source yet.
Frost Kill Temperature
25°F
Where cold starts killing growing tissue. Not a winter-survival floor — a dormant perennial takes far colder, which its hardiness zone answers.
We haven't confirmed this against a published source yet.
Days to Maturity
55 days
We haven't confirmed this against a published source yet.
GDD Required
600+
Growing degree-days of accumulated warmth it needs to mature — humid summers reach this faster than cool coastal ones.
We haven't confirmed this against a published source yet.
Mature Height
0.5 ft
We haven't confirmed this against a published source yet.
Frost-Free Days
40+
The frost-free stretch it needs start to finish — short-season areas may need an indoor head start.
Growable Ground plant catalog
Start the season right
Plant sweet alyssum in full sun with at least 6 hours of direct sun. It grows in the cool halves of the year, so sow it in spring or late summer rather than waiting for midsummer heat. We haven't confirmed this against a published source yet.
Match the soil
Sweet Alyssum prefers pH 6 to 7. We haven't confirmed this against a published source yet. 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. We haven't confirmed this against a published source yet. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at its peak
Cut sweet alyssum blooms in the cool of the morning, just as they open, for the longest display.
Where Sweet Alyssum thrives
Sweet Alyssum overwinters in USDA zones 5 through 9 and is grown as a summer annual wherever the season is long enough. 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 5–9 spans average winter lows from -20°F to 30°F (USDA PHZM 2023). Across the 50 states and DC, that band covers 25 outright and splits 25 more down the middle.
Zones 5–9·Hardiness bandOpen map →
This map is derived from the USDA ARS / PRISM Plant Hardiness Zone Map (2023) and is not the official USDA Plant Hardiness Zone Map.
Where Sweet Alyssum stands, state by state
Sweet Alyssum is rated for zones 5–9 — a cold floor USDA puts at -20 to -10°F. Across the 50 states and DC, 25 sit fully inside that band, the line runs through 25 more, and 1 sits outside it — and inside every split state, the same line runs on at county grain.
Fully inside zones 5–9
25 states
3 of 25 shown
The line runs through
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 Sweet Alyssum
Growing guides for sweet alyssum
In rotation planning, sweet alyssum counts as a Brassica — beds recover best when brassica 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 annual flower
Good to know
Sweet Alyssum is a standout pollinator plant — high value to bees and other pollinators. We haven't confirmed this against a published source yet.
Your land is one point inside Sweet Alyssum'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 Sweet Alyssum will thrive on your land
Zone averages are a start. Your soil pH, drainage, sun exposure, and frost dates shape whether sweet alyssum actually takes. We score it against the mapped and modelled 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
How we know this about Sweet Alyssum
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
Frequently asked questions
Can I grow Sweet Alyssum in my zone?
Sweet Alyssum overwinters in USDA hardiness zones 5 through 9 (NC State Extension Gardener Plant Toolbox) and is grown as a summer annual wherever the season is long enough. Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
When should you plant Sweet Alyssum?
Sweet Alyssum is a cool-season crop, so it goes in during the cool halves of the year — early spring, and again in late summer for a fall planting — rather than at the height of summer heat. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Sweet Alyssum need?
Sweet Alyssum needs full sun — a spot that catches at least 6 hours of direct summer sun a day. We haven't confirmed this against a published source yet. 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 Sweet Alyssum need?
Sweet Alyssum prefers soil pH 6 to 7, on well-drained ground. We haven't confirmed this against a published source yet. Your report scores your parcel's mapped soil against that using USDA SSURGO data.
Does Sweet Alyssum attract pollinators?
Yes — sweet alyssum's flowers are a strong nectar and pollen source for honeybees, native bees, and butterflies. We haven't confirmed this against a published source yet.
Keep exploring Sweet Alyssum
Sweet Alyssum state by state
Every state sweet alyssum's zone reaches — 3 link straight to that state's sweet alyssum growing page; the rest open the state's full growing guide.