Lobularia maritima 'Carpet of Snow'
flowerSweet alyssum is a low, mat-forming annual in the mustard family, native to the Mediterranean coast, that smothers itself in tiny four-petaled flowers with a soft honey fragrance. Carpet of Snow is the classic pure-white form, only three to nine inches tall but spreading wider into a dense flowering carpet. It blooms from early in the season until frost, tucking along bed edges, between pavers, and over the rims of containers and hanging baskets. Beyond its looks and scent, it is one of the most valuable beneficial-insect plants a gardener can grow.
Sun
full sun
Water
Every 3 days
Bloom
~55 days
Difficulty
easy
Lifecycle
annual
One season, then done
Spacing
6-9 in. apart
Planting Depth
Surface sow — needs light
Soil pH
6.0-7.5
Soil Type
Average, well-draining
Hardiness Zones
Zones 3 – 10
Grown as an annual — this range is its winter hardiness, but you can grow it for a single season in any zone.
When to Fertilize
Generally not needed; too much nitrogen reduces flowering
Fertilizer
None or very light balanced at sowing
Sweet alyssum is very easy from seed, sown directly or started indoors; just barely cover the seed or press it onto the surface, since it needs light to germinate. Give it full sun in cool climates, but in hot regions afternoon shade keeps it looking better. It is undemanding about soil as long as drainage is good, and it flowers best in lean ground, since heavy feeding pushes leaves at the expense of bloom. Its one quirk is heat: growth and flowering slow in midsummer and plants look ragged, then revive and rebloom as cool weather returns in fall. To push more flowers, shear plants back by a third to a half when bloom slackens. It may self-seed modestly, with volunteers reverting to white.
🌼 Have a different variety?Cultivars of the same species usually share the same basic care — they differ mainly in flower color, height, and bloom form, not in how you grow them. So this guide still applies even if your exact variety isn't the one shown.
Direct sow
Apr 1
Projected first bloom
May 26
Good neighbors that attract beneficial insects or deter pests
Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide
The flowers attract hoverflies whose larvae eat hundreds of aphids; plant at the edges of every vegetable bed
Cabbage loopers and caterpillars
Draws braconid wasps that lay eggs in pest caterpillars
Supports parasitic wasp populations that keep whitefly numbers low
Sweet alyssum is grown for its flowers and the beneficial insects it feeds rather than for food, though the blooms are edible with a mild honey-cress flavor and make a pretty garnish. The most useful maintenance is shearing: cut whole plants back by about half every six to eight weeks to keep them dense, blooming, and from exhausting themselves into seed. Site it deliberately as a banker plant along the edges of vegetable beds, where its flowers draw hoverflies and parasitic wasps right to the crops that need protecting.
Sweet alyssum is primarily a pollinator and beneficial-insect plant rather than a food crop, and its real value is ecological: the nectar-rich flowers are highly attractive to bees, butterflies, hoverflies, and tiny stingless parasitic wasps, and it is interplanted in commercial organic lettuce and broccoli fields in California to attract the natural enemies of aphids and caterpillars. The flowers are edible, carry a mild honey fragrance, and contain coumarins with mild anti-inflammatory properties, but they serve as a delicate garnish, contributing scent and appearance rather than meaningful nutrition.
For educational and informational purposes only — HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.