Alyssum is a small and pretty, easy to grow summer flowering hardy annual that goes by several common names: sweet alyssum or Alison because of its strong, sweet scent and ‘carpet of snow’ for its masses of tiny white blooms. There are pink and purple-flowered varieties, as well as white, and the flowers are often produced in such profusion that the slender lance-shaped green leaves are barely visible.
The botanical name of alyssum is Lobularia maritima. As the second name suggests, this plant originates from seaside environments, from the Mediterranean and Canary Islands, so it grows very well in coastal areas. It’s also a useful bedding plant for border edges, banks and pots. Alyssum plants are small, compact, and slightly spreading in habit, growing to a maximum of 10cm high and 15cm wide. Alyssum flowers are very attractive to pollinating and beneficial insects so it makes a good edging plant to sow around vegetable beds to entice insects to pollinate flowers and help control pests.
Alyssum is a hardy annual flower that is beloved for its sweet fragrance, delicate clusters of blooms, and versatility in the garden. Growing alyssum from seed is an easy and affordable way to add this charmer to beds, borders, and containers for a season of enchanting blossoms
In this complete guide for beginners, you’ll learn all the key tips for successfully starting alyssum from seed and caring for plants throughout the growing season.
What is Alyssum?
Alyssum (Lobularia maritima) is a low-growing annual that reaches just 4 to 12 inches tall. Native to Southern Europe and the Mediterranean, it thrives in cool, sunny conditions.
This versatile plant is grown as:
- Groundcover
- Edging
- Container filler
- Rock garden plant
Delicate clusters of tiny cross-shaped flowers bloom nonstop from spring through fall frost. Popular colors include white, purple, pink, lavender and peach. Some varieties have fragrant blooms or attractive gray-green foliage.
Thanks to prolific self-seeding, alyssum often reappears each year. The nectar-rich blossoms also lure in pollinators and beneficial insects.
When to Start Alyssum Seeds
Alyssum germinates best at cool temperatures of 60 to 70°F. It can withstand light frost once established.
In spring, sow seeds indoors 6 to 8 weeks before your last expected frost date Grow on at 60 to 65°F
Harden off and transplant seedlings into garden beds or containers after danger of frost. Space plants 8 to 12 inches apart in full sun.
You can also direct sow seeds outdoors once the soil has warmed up and frost danger has passed. Scatter seeds into prepared soil and lightly cover.
In fall, sow alyssum seeds in containers or garden beds about 8 to 10 weeks before your first expected fall frost. This will allow time for flowers to develop before cooler weather arrives.
How to Start Alyssum Seeds Indoors
Step 1. Use a seed starting mix and trays or pots with drainage holes. Shallow trays work well.
Step 2. Scatter seeds across the mix surface. Do not cover them, as light aids germination.
Step 3. Mist gently to water and place trays in a warm spot around 70°F.
Step 4. Once seedlings emerge in 5 to 10 days, move to a sunny window or under grow lights. Grow on at 60 to 65°F.
Step 5. Harden off plants for 7 to 10 days before transplanting into the garden after frost danger has passed.
Direct Sowing Alyssum Outdoors
For easiest growing, sow alyssum seeds right into garden beds or containers.
Step 1. Prepare soil and rake smooth. Choose a site with full sun and average, well-draining soil.
Step 2. Sprinkle seeds 6 inches apart across the soil surface once temperatures are warm, after your last spring frost date.
Step 3. Gently press seeds into the soil. Do not cover deeply since they need light to sprout.
Step 4. Keep the top 1 inch of soil evenly moist until seeds germinate in 5 to 10 days.
Step 5. Once seedlings are 2 to 3 inches tall, thin to final spacing of 8 to 12 inches apart.
Growing Alyssum in Containers
The trailing habit of alyssums makes them ideal spillers for containers. Follow directions above for sowing. Use a quality potting mix and provide full sun. Let soil dry slightly between waterings. Add short twiggy branches as needed for support. Shear back leggy growth to encourage fullness.
Ongoing Care of Alyssum Plants
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Deadhead spent blooms regularly to promote new flowers.
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Apply a balanced liquid fertilizer monthly.
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Improve airflow and treat any signs of powdery mildew.
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Pinch back plants by half after initial blooming for a second flush of flowers.
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Pull up expired plants after frost or leave some to self-seed next year.
With proper sowing and care, alyssums are easy to grow from seed and provide endless delicate blossoms to enjoy.
Tips for Growing Different Alyssum Varieties
Many color and form options exist beyond classic white alyssum:
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Easter Bonnet Mix – Vibrant blend of purple, pink, lavender and white large blooms.
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Clear Crystal White – Masses of bright white flowers on mounding 6″ plants.
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Carpet of Snow – The standard tiny white blooms; very compact and long blooming.
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Rosie O’Day – Unique soft pink trailing blooms perfect for hanging baskets.
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Purple Prince – Rich royal purple flowers on dense 8″ mounds.
With countless varieties, it’s fun to experiment with growing different types of alyssums from seed.
Using Alyssums as Companion Plants
Interplant alyssum throughout the vegetable garden. Research shows they attract beneficial hoverflies, whose larvae eat aphids. The flowers also bring in pollinators. Place near cabbage, broccoli, kale and other brassicas prone to aphids. The colors contrast beautifully with edibles too.
Thanks to self-seeding, once established, alyssums often come back each year. Enjoy season after season of their nonstop blossoms in beds, borders and containers. With the right tips for sowing and care, alyssums are easy to grow from seed and provide a delightful floral carpet.
Growing alyssum: problem solving
Slugs
Slugs can eat the young seedlings: protect with an environmentally friendly bait or barrier or start seedlings in trays and plant out when the young plants are large enough to withstand some slug damage.
Downy mildew
Downy mildew can occur during spells of wet weather as a whitish or white, purple-tinged coating on the leaves. Ensure alyssum is planted in well-drained soil and at the recommended spacings so there’s plenty of air movement around the plants.
How to grow alyssum from seed[image id=”133478″ size=”landscape_thumbnail” align=”none” title=”2048×1365-Alyssum-SEO-GettyImages-1329401167″ alt=”Alyssum seedlings. Getty Images” classes=””] Alyssum seedlings. Getty Images
To sow seed where alyssum is to flower, take out shallow drills and water the ground thoroughly before sowing, then cover with 0.5cm of soil. Thinning the resulting seedlings to 15cm apart will produce larger and sturdier individual plants.
Sow alyssum under cover in autumn or early to mid-spring: an unheated greenhouse, porch or cold frame is fine, as alyssum is a hardy annual and tolerates a little frost. Sowing in warmth will produce earlier flowers. Use modular seed tray inserts, fill with multi-purpose compost, firm lightly and water well before sowing several seeds to each cell. Cover lightly with 0.5cm of compost. Thin seedlings to one per cell.
How to Grow Alyssum from Seed | An Easy Planting Guide
FAQ
How long does it take to grow alyssum from seed?
- Germination: Alyssum seeds typically germinate within 5 to 14 days.
- Seedling Growth: After germination, it takes roughly 45 days for the seedlings to reach the blooming stage.
- Total Time: From seed to bloom, expect it to take about two months.
Do you need to soak alyssum seeds before planting?
PLANTING GUIDE:
Seeds do not need pre-treatment prior to planting. Alyssum requires evenly moist, well-drained soil or may die if grown in water soaked soil. Sow seeds indoors: in flats 6-8 weeks before the last average frost date in your region.
Does alyssum come back every year?
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Annual Behavior:Sweet alyssum is typically treated as an annual, meaning it completes its life cycle within one year.
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Self-Seeding:As a member of the Mustard family, it produces many seeds, and these readily germinate if allowed to fall back into the soil.
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Warm Climate Persistence:In warmer climates, sweet alyssum can survive the winter and continue to bloom through the following year.
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Returning from Seed:Even in climates where it dies back in the winter, it often returns the following spring from seeds that have germinated.
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Temperature Sensitivity:Sweet alyssum thrives in cooler temperatures, so it may fade or stop blooming during the hottest parts of the summer, but can re-bloom in the fall.
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Sowing Seeds:In climates with freezing winters, to ensure its return, you can allow the plant to produce seeds and then they will naturally re-seed in the spring.
How many alyssum seeds per hole?
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Direct sowing:If sowing directly into the garden, space seeds about 6 inches apart, says Burpee Seeds.
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In seed flats:You can scatter 4-8 seeds per cell in a 72-cell flat, says Eden Brothers. Press the seeds lightly into the surface of the soil, says Johnny’s Seeds.
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Thinner spacing:If you want more space between plants, you can thin out the seedlings to 6-8 inches apart once they have developed a few true leaves, says Johnny’s Seeds.
How do you plant Alyssum?
2. Choose the best location for planting alyssum Alyssum is a low-lying spreading plant that is about 3-9 inches tall and 6-12 inches wide (depending on variety). Plant alyssum in a location that gets plenty of sunlight – at least 6 hours. Alyssum grows well in average soil, but it must be well-draining; it does not like wet feet.
Can you grow sweet alyssum from seed?
It will make your garden look nicer and bring in pollinators and good bugs. With its dainty clusters of tiny flowers in shades of white, purple, pink and more, sweet alyssum is one of the easiest annuals to grow from seed. Starting these fragrant flowers from seed yourself can save money over buying bedding plants.
How long does it take Alyssum seeds to grow?
Plant alyssum seeds after all threats of heavy frosts have passed. A little light frost is okay. You don’t really have to make a hole, simply loosen up the soil and scatter the seeds. Keep the soil moist until seeds germinate (usually in about eight to 10 days).
Can you grow Alyssum indoors?
Starting indoors extends your bloom season by a few weeks. You can also sow more seeds outdoors once temperatures are warm. The easiest way to grow alyssum is by direct sowing the seeds right in the garden bed or containers. Follow these tips: Wait until after your last spring frost to sow. Soil temperature should be at least 60°F.
Where do Alyssum plants grow?
Warm humid summers with high summer rainfall and mild winters. Includes coastal Queensland and northern NSW from north of Mackay to just south of Coffs Harbour. Alyssum plants commonly self-seed in the garden. Self-seeding plants drop seeds onto the soil at the end of the season that may germinate and grow without help the following season.
When should I plant Alyssum seeds?
In fact, alyssum is often grown as a winter annual in warm regions where the temperatures do not drop below freezing. Planting alyssum seeds in the fall or winter can give you a head start on the growing season and ensure beautiful blooms in the spring. Another factor to consider when starting alyssum seeds is the amount of sunlight they need.