When to Plant Sweet Alyssum
Low-growing carpet of tiny, honey-scented flowers. Perfect edging plant and living mulch that attracts beneficial insects.
The Short Answer
How to Grow Sweet Alyssum
Sweet alyssum is the most useful edging plant in the garden — a living carpet of tiny, honey-scented flowers that attracts hoverflies, parasitic wasps, and other beneficial insects that prey on aphids, caterpillars, and other garden pests. Interplant alyssum throughout the vegetable garden as a 'living mulch' that provides biological pest control while suppressing weeds and retaining soil moisture. Seeds are dust-fine and need light to germinate — scatter on the surface and mist, don't cover. Self-seeds aggressively in mild climates, creating permanent ground cover that returns each year.
Starting Seeds Indoors
Begin sweet alyssum seeds indoors 6 weeks before your average last frost date. Seeds need soil temperatures of at least 50°F to germinate, which typically takes 5-10 days. Provide 12 hours of light per day using a south-facing window or grow lights.
Transplanting
Move seedlings outside 2 weeks before your last frost date, once soil temperatures reach 50°F. Harden off seedlings for 5 days before transplanting by gradually exposing them to outdoor conditions.
Direct Sowing
Sweet Alyssum can be direct sown 2 weeks before your last frost date. , spaced 6" apart.
Fall Planting
Sweet Alyssum are planted in fall, 8 weeks before your average first frost date. , 6" apart.
Growing Tips
Scatter seeds on soil surface — they need light to germinate. Self-seeds aggressively in mild climates. Shear back in midsummer heat and it rebounds for fall. Exceptional at attracting hoverflies and other beneficial predatory insects.
Companion Planting
Good companions:
Sweet Alyssum Planting Dates by State
Click your state for sweet alyssum planting dates specific to your location:
Last reviewed: March 29, 2026