How to Grow Sweet Alyssum
Lobularia maritima
Honey-scented, low-growing annual that carpets borders and containers with clouds of tiny white or lavender flowers all season.
By the Plants by Zone Editorial Team · Reviewed June 1, 2026
About sweet alyssum
Sweet alyssum is one of the easiest and most rewarding annuals you can grow, forming a dense 4–6 in carpet of tiny four-petaled flowers that smell unmistakably of fresh honey. It thrives in cool weather, tolerates light frost, and blooms from early spring through fall with a brief pause in midsummer heat — shear it back then and it rebounds with a second, often even stronger flush. The white cultivar 'Carpet of Snow' is a classic, but modern selections in lavender, rose, and deep purple are equally vigorous and pair beautifully with taller annuals at the border edge.
When to plant and harvest sweet alyssum
Timing is relative to your frost dates. Find your USDA zone for exact dates, or browse the month-by-month calendars.
Start seeds indoors
4–6 weeks before last frost (optional — direct-sowing is easier and equally fast)
Transplant outdoors
2–4 weeks before last frost; tolerates light frost once established
Direct sow
As soon as soil can be worked in early spring (tolerates light frost), and again in late summer for a fall flush
Harvest
Not applicable — ornamental
Free planting calendar
Put sweet alyssum on your own planting calendar
Pick your zone, and we'll build a month-by-month sow, transplant & harvest chart with sweet alyssum already on it — print it or save it as a PDF.
Free · no signup needed
How to grow sweet alyssum step by step
- 1
Surface-sow on lightly raked, firmed soil — scatter seed thinly and press it in without covering, since light triggers germination.
- 2
Water gently with a fine mist until seedlings are established; avoid dislodging the tiny seeds.
- 3
Thin or transplant seedlings to 6–8 in apart once they have their first true leaves.
- 4
Allow to bloom freely through spring; if flowering slows in midsummer heat, shear the entire plant back by one-third — it flushes new growth and reblooms strongly in fall.
- 5
Let a few plants go to seed at the end of the season; sweet alyssum self-sows freely and will naturalize a patch over time.
Common problems growing sweet alyssum
⚠ Mid-season bloom slump in summer heat
Normal behavior — shear plants back by one-third when flowering slows in hot weather; water well and they rebound vigorously once temperatures ease in late summer.
⚠ Aphids clustering on tender new growth
Small infestations are harmless; blast with water or apply insecticidal soap. Alyssum is an excellent trap crop that draws aphid predators, so moderate colonies often disappear on their own.
⚠ Leggy, sparse plants with few flowers
Usually caused by too much shade or rich, nitrogen-heavy soil; move to a sunnier spot or lean soil, and shear back to encourage bushy, floriferous regrowth.
⚠ Damping-off in seedlings
Caused by overwatering in cool, poorly drained soil; improve drainage, water less frequently, and allow the soil surface to dry slightly between waterings.
✗ Keep away from
🧺 Harvesting sweet alyssum
Sweet alyssum is grown for its flowers and fragrance, not for harvest. To maximize the season, shear the entire plant back by one-third immediately when bloom slows in summer heat — do not be timid, even a hard cut will regenerate quickly. The honey fragrance is strongest on warm mornings; the tiny flowers are edible with a mild, slightly peppery taste and make delicate garnishes for desserts and cocktails, though alyssum is grown ornamentally, not as a culinary crop.
Sweet Alyssum: frequently asked questions
When should you plant sweet alyssum?＋
In most regions you start seeds indoors 4–6 weeks before last frost (optional — direct-sowing is easier and equally fast), then transplant 2–4 weeks before last frost; tolerates light frost once established — or direct sow as soon as soil can be worked in early spring (tolerates light frost), and again in late summer for a fall flush. Timing is relative to your last frost, so find your USDA hardiness zone for the exact planting dates where you live.
How do I get sweet alyssum to keep blooming after it stops in summer?＋
Shear the plant back by one-third with scissors or hedge shears as soon as flowering slows — this is the key trick. Water and feed lightly afterward, and the plant will push new growth and bloom prolifically again in the cooler weeks of late summer and fall, often looking better than it did in spring.
Does sweet alyssum come back every year?＋
It is a frost-tender annual that will not survive hard freezes, but it self-sows so freely that it effectively reappears on its own each spring once established. Let a few plants go to seed at the end of the season and you will likely see seedlings the following year without replanting.
Sources & review
Written and maintained by the Plants by Zone Editorial Team. Planting times are based on USDA hardiness zones and NOAA frost-date normals, with care guidance drawn from Cooperative Extension sources. Last reviewed June 1, 2026.
USDA Plant Hardiness Zone MapNOAA U.S. climate normalsCooperative Extension
Grow sweet alyssum in your zone
See exactly when to plant and what else to grow alongside sweet alyssum, tailored to your USDA hardiness zone.
