Sweet Alyssum Companion Plants
Flower50 days to maturity
Sweet alyssum is a low, carpeting annual covered in tiny honey-scented white, pink, or purple flowers from spring through fall. Its real garden value is as an insectary and living-mulch plant: the clusters of minute blooms are perfectly sized for hoverflies and parasitic wasps whose larvae devour aphids, while its dense mat shades soil and suppresses weeds.
Companion Checker: what grows well with Sweet Alyssum?
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Companion Planting Strategy for Sweet Alyssum
Sweet alyssum is grown as an underplanting that recruits aphid-eating hoverflies and parasitic wasps while carpeting bare soil between crops. Tuck it around lettuce, tomatoes, and potatoes as a low living mulch that feeds beneficial insects without competing for height or light.
Best Companion Plants for Sweet Alyssum
These plants grow well alongside Sweet Alyssum — providing pest control, attracting pollinators, or making better use of your garden space.
Sweet alyssum's low mat shades the soil and conserves moisture around lettuce while drawing hoverflies that keep lettuce aphids in check.
Sweet alyssum interplanted at the base of tomatoes attracts hoverflies and parasitic wasps that prey on aphids and other soft-bodied pests.
Sweet alyssum lures hoverflies and predatory insects that help control aphids and the soft-bodied pests around potatoes while covering open ground.
How to Grow Sweet Alyssum
- Botanical name
- Lobularia maritima
- Family
- Mustard/Brassica (Brassicaceae)
- Sun
- Full sun to part shade; tolerates afternoon shade in heat
- Water
- About 1 inch per week; keep soil lightly moist, though it is drought tolerant once established
- Soil
- Average, well-draining soil, pH 6.0-7.0
- Spacing
- 6-10 inches apart for a solid carpet
- Planting depth
- Surface-sow and press seeds into the soil without covering, as they need light to germinate
- Germination
- 5-14 days at 55-70F
- Days to maturity
- About 6-8 weeks (50-60 days) from seed to bloom
- When to plant
- Direct sow around the last spring frost; it is cool tolerant and can be resown for fall
- Harvest
- Grown for bloom, not harvest; shear plants back lightly in midsummer to spur a fresh flush of flowers
Common Sweet Alyssum Problems
Plants stop blooming and look ragged in midsummer heat
Shear the whole plant back by about a third and water well; cooler weather and the trim will trigger a new wave of flowers.
Downy mildew (yellowing leaves with fuzzy growth underneath)
Space plants for airflow, avoid overhead watering, and remove infected plants; rotate away from other brassicas.
Flea beetles peppering leaves with tiny shot holes
Since alyssum is a brassica, protect seedlings with row cover, dust with diatomaceous earth, and keep plants vigorous to outgrow damage.
Aphids and root rot in poorly drained, soggy soil
Improve drainage and avoid overwatering; rinse off aphids and let the hoverflies the plant attracts do the rest.
Sweet Alyssum Companion Planting FAQ
What are the best companion plants for sweet alyssum?
Sweet alyssum is an outstanding companion for lettuce, tomatoes, and potatoes, acting as a living mulch and drawing in hoverflies and parasitic wasps that control aphids. It works as a low underplanting beneath almost any vegetable that benefits from natural aphid control.
What should you not plant with sweet alyssum?
Sweet alyssum has no real plant antagonists, but because it is a brassica it can share flea beetles and downy mildew with cabbage-family crops, so monitor when planting them together. Otherwise it is one of the safest companions you can grow.
Does sweet alyssum really attract beneficial insects?
Yes, it is one of the most reliable insectary plants in the garden. Its tiny, shallow flowers are ideal for hoverflies, lacewings, and parasitic wasps, whose larvae and offspring prey heavily on aphids in surrounding crops.
Will sweet alyssum come back every year?
Sweet alyssum is grown as an annual and dies back in cold winters, but it self-seeds freely and often reappears in the same area each spring. In mild, frost-free climates it can behave as a short-lived perennial.
More flower companions
Plan Your Sweet Alyssum Garden
Use our interactive tools to design the perfect garden with Sweet Alyssum and its companions.