How to Grow Alyssum
Alyssum At a Glance
Difficulty
Easy
Category
Flower
Sun Exposure
Full Sun, Partial Sun
Frost Tolerance
Frost Hardy
Cold Hardiness
Survives to -7°C
Plant Family
Brassicaceae
Growing Season
Cool & Warm Season
Plant Lifecycle
Annual
How to Start It
★ Recommended for beginners
Alyssum shrugs off light frost, so scatter the seed about 2 weeks before your last spring frost, right where you want it to bloom. The seed needs light to sprout, so press it into the soil and barely cover it, no deeper than 0.5 cm. Seedlings appear in 7 to 14 days: thin them (pull the extras so each has room) to about 15 cm apart.
Alyssum is one of the easiest flowers to grow from seed, and its honey-scented carpets pull in bees and the hoverflies whose young eat aphids, so it is a great friend to tuck beside vegetables. It flowers about 45 days after sowing and often sows itself for next year.
When To Start
First chance to plant
14 Days Before Last Frost
Last chance to plant
30 Days Before First Frost
When should you plant Alyssum?
Your planting dates depend on your local climate. Sign up and add your location to unlock personalized dates.
Your Alyssum Planting Window
Start planting
May 15, 2026
Last chance
Sep 10, 2026
Your Alyssum Calendar
Set your location to turn these into exact dates and reminders.
Scatter alyssum seed outdoors and barely cover it
2 weeks before your last frost· every year
Cut alyssum back by half if it stops flowering in the heat
75 days after your last frost· every year· optional
Did you water your alyssum seedlings today? Keep the top of the soil damp until they are up and growing.
About 1 days after you plant it
Time to thin the alyssum seedlings: snip the extras at soil level so each one has room to grow.
About 24 days after you plant it
Your alyssum is off to a good start! Thin crowded seedlings so each little plant has room to spread.
About 29 days after you plant it
Almost bloom time for your alyssum. If it slows down in hot weather, trim it back a little and it will flower again.
About 44 days after you plant it
Picking time may be here: check your alyssum.
About 45 days after you plant it
The Journey Ahead
Alyssum's Lifecycle
Seedling
Mature Plant
Seed Production
Step 2
Planting & Sprouting
Expect sprouts in 7–14 days
Growing Tips
- 1Grow alyssum in full sun, though it still flowers in part shade.
- 2It is happy in ordinary soil, so a little compost mixed in at planting is all it needs.
- 3Water when the top of the soil is dry, and water pots more often in hot weather.
- 4In pots, feed with compost tea once a month to keep the flowers coming.
- 5If the plants stop flowering in a summer heat wave, cut them back by about half and they bloom again when it cools.
- 6Spray aphids off with a strong stream of water, and give the plants room so air can move between them.
Seedling Phase
Step 3
Growth & Maturity
~45
Days to Maturity
12 cm
Mature Height
30 cm
Mature Width
Pests to Watch For
Diseases to Watch For
Mature Plant
Step 4
Harvesting
Harvest Window
30 days
When to Pick
Flowers when fully bloomed
How to Harvest
- 1Alyssum is grown for its flowers, so there is nothing to pick, only a little care.
- 2Snip a few stems for a tiny bouquet whenever you like, since cutting does not slow it down.
- 3Shear the whole plant back by about half if it gets long and straggly in midsummer.
- 4Leave a few plants to drop their seed in fall, and new seedlings often pop up the next spring.
Step 5
Saving Seeds
How to Save Seeds
Alyssum flowers are visited by insects, so different colours grown close together can cross, but plain white alyssum grown on its own stays true. Hybrid F1 seeds will not grow true. After the flowers fade, let the small, flat, round pods turn brown and dry on the plant. Cut the stems over a bag or bowl and rub the pods to free the tiny seeds, then gently blow away the bits of pod. Store the seeds labelled in a cool, dark, dry place, where they keep about 3 years.
Seed Production
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