Snow Princess® sweet alyssum makes a vigorous flowering groundcover. Photo: Proven Winners

One of the most enduring garden annuals is sweet alyssum. This old-time favorite produces dainty honey-scented flowers throughout the growing season. The mounding or trailing habit is well-suited for containers, hanging baskets and garden beds. A member of the mustard family, sweet alyssum is forgiving of varying soil and light conditions. Native to the Mediterranean, this reliable heirloom overwinters as a short-lived perennial in warmer regions.

Sweet alyssum is a butterfly and insect pollinator magnet, and hummingbirds love it, too. With so much going for it, what’s not to like?

On this page: The Basics | Planting | Care | Choosing the Right Alyssum | Pictures | Landscaping Tips

ALYSSUM BASICS

Zones:

Annual up to Zone 8; short-lived perennial in Zones 9-11.

Height/Spread:

Sprawling or mounding habit, with plants growing 4-10 inches tall, 10-48 inches wide, with branches trailing up to 36 inches long.

Exposure:

Sweet alyssum blooms best with at least six hours of full sun, but can tolerate partial shade. In warmer climates, plants perform best with protection from hot afternoon sun.

Bloom time:

Spring until the first hard frost.

Color and characteristics:

Plants have tiny, hairy, oval leaves that are green, blue-green, or variegated. Branching stems bear prolific clusters of 1/4-inch wide four-petaled blossoms. The delightful honey-scented flowers come in shades of white, pink, rose, lavender, purple and apricot.

Types:

Older varieties (Lobularia maritima) are easily grown from seed and self-sow readily from year to year in temperate climates. Referred to as cool-season annuals, they are much more cold hardy than the newer hybrids, as well as being more drought tolerant. They bloom best in spring and fall, with a lull during hot summer months. A newer generation (Lobularia hybrids )—developed for extreme vigor and bigger plant size—bloom nonstop throughout the growing season. These varieties take the heat much better than L. maritima types, but are not drought tolerant. They are sterile (not seed-producing), so are only grown from cuttings.

Toxicity:

Sweet alyssum is not known to be toxic to pets and children, and flowers are edible.

PLANTING INSTRUCTIONS

Mass-Planting Alyssum

When to plant:

Sow seeds indoors in flats several weeks before the last average frost date in your region, or sow directly outdoors after all danger of frost is past. For nursery starts, plant outside any time after the last frost.

Where to plant:

In the garden, plant in full sun to partial shade in average, well-draining soil. For baskets and containers, make sure there is adequate drainage.

How to plant:

Broadcast seeds in flats indoors, or well-amended soil outside. Don’t cover seed, as light will aid in germination. Keep moist until germination, 7-20 days. Transplant seedlings when there are at least two sets of secondary leaves, allowing 6 inches of space between plants. For containers, place plants in high quality, well-draining potting mix and allow 6-12 inches of space between plants, depending on the variety. Water plants thoroughly.

SWEET ALYSSUM CARE

Pruning and deadheading:

Newer hybrids flower nonstop and need no deadheading. For older cultivars, shear plants back by half in mid-summer and fertilize to stimulate new growth and flowers.

Soil:

For containers, use a quality all-purpose potting mix that drains well. In the garden, soil should be well amended with good drainage. Older varieties are tolerant of poorer soils and somewhat dry conditions.

Amendments & fertilizer:

Sweet alyssum are moderate feeders. Add a time-release fertilizer to the soil at the time of planting. When blooms are spent, apply water-soluble fertilizer to stimulate new growth; reapply monthly.

Watering:

Keep plants well-watered, but don’t overwater. For containers, allow the top two inches of soil to dry out between each watering. Check daily in hot weather, as pots can dry out quickly. Older varieties are more drought-tolerant, while newer hybrids need more water.

Diseases and pests:

Sweet alyssum is not prone to pests, but can get stem rot or leaf blight if planted in an overly moist site such as shade or a bog. Seedlings are susceptible to damping-off disease.

Deer resistance

Deer have a keen sense of smell, which causes them to be overwhelmed by scented plants. Because of this, they will shun sweet alyssum.

For more on growing sweet alyssum:

Succeeding with Sweet Alyssum

HOW TO CHOOSE THE RIGHT ALYSSUM

With so many uses for sweet alyssum, here are a few tips to consider when selecting:

For containers, hanging baskets and window boxes:

Choose trailing varieties, and combine with other plants with upright and mounding habits for the “thriller, filler, spiller” effect.

For edging and between pavers:

Use varieties that stay compact so that plants don’t spill into areas meant for walking.

For bedding displays:

Mass plants together for greater impact, and to keep plantings in scale with the landscape.

SWEET ALYSSUM VARIETIES

Swipe to view slides

Photo: Proven Winners

Snow Princess® Buy now from Proven Winners
Lobularia hybrid

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Sprawling habit, with plants reaching 4-8 inches tall, 24-48 inches wide, and branches trailing up to 24 inches long

Exposure:

Full sun to partial shade

Bloom Time:

From the time of planting until the first hard frost

Color:

White

The flowers—larger than most—are highly fragrant. Plants are cold and heat tolerant, as well as vigorous, producing lots of blooms all season long. With a mounding, cascading habit; Snow Princess is well-suited for containers. Plant by itself or in combination with other vigorous plants such as ‘Victoria Blue’ salvia, dusty miller, or Superbells®. This sterile variety is grown only from cuttings, as it does not produce seed.

Photo: Proven Winners

Blushing Princess® Buy now from Proven Winners
Lobularia hybrid

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Sprawling habit, with plants reaching 4-8 inches tall, 24-36 inches wide, with branches trailing up to 36 inches long.

Exposure:

Full sun to partial shade

Bloom Time:

From the time of planting until the first hard frost

Color:

Pale lavender

The exceptionally long trailing habit makes this a great choice for hanging baskets or containers. One of the largest hybrids, Blushing Princess performs best in larger pots that can handle the higher watering needs. Plant by itself or combine with other vigorous plants such as Supertunias® or sweet potato vine. This sterile cultivar is grown only from cuttings, as it does not produce seed.

Photo: Proven Winners

Dark Knight™ Buy now from Proven Winners
Lobularia hybrid

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Sprawling habit, with plants reaching 4-6 inches tall, 18-24 inches wide, with branches trailing up to 24 inches long.

Exposure:

Full sun to partial shade

Bloom Time:

From the time of planting until the first hard frost

Color:

Deep purple

The trailing habit makes this a good choice for hanging baskets and containers. Due to higher water needs, place in larger containers so that plants don’t dry out during hot summer months. Combine with other vigorous growers such as Supertunias or sweet potato vine. This sterile cultivar is grown only from cuttings, as it does not produce seed.

Photo: Ball Horticultural Company

‘Snow Crystals’
Lobularia maritima

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Mounding and spreading habit, with plants reaching 4-10 inches tall and 12 inches wide.

Exposure:

Full sun to partial shade

Bloom Time:

Late spring to frost

Color:

White

This variety, which appeared on the market in the 1980s, represents an improvement over older varieties, with larger flowers, better heat tolerance and a longer bloom time. The uniform habit makes this a good choice for bedding displays, as a groundcover, along pathways and as border edging.

Photo: Ball Horticultural Company

‘Easter Bonnet Deep Pink’
Lobularia maritima

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Mounding and spreading habit, with plants reaching 4-10 inches tall and 10-12 inches wide.

Exposure:

Full sun to partial shade

Bloom Time:

Early summer to fall

Color:

Rich pink

The mounding and spreading habit makes this a good choice for along pathways and as edging in mixed borders. Other colors in this series come in shades of violet, lavender, rose and pastel pink.

Photo: Paul2032 / The National Gardening Association / Creative Commons

Wonderland® Deep Rose
Lobularia maritima

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Mounding habit, with plants reaching 4-6 inches tall and 10 inches wide.

Exposure:

Full sun to partial shade

Bloom Time:

Early summer to early fall

Color:

Rich rosy pink

One of the most vivid pink varieties, the compact, uniform habit makes this a good choice between pavers, in rock gardens, or in containers. Other colors in this series come in shades of white, pink, purple and lavender.

Photo: Steffen Hauser / botanikfoto / Alamy Stock Photo

‘Violet Queen’
Lobularia maritima

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Mounding habit, with plants reaching 4-6 inches tall and 12 inches wide.

Exposure:

Full sun to partial shade

Bloom Time:

Spring to mid-fall

Color:

Violet purple, with top blossoms fading to pale lavender

This compact variety is good as a groundcover, along pathways, for rock gardens and between pavers.

Photo: All-America Selections

‘Royal Carpet’
Lobularia maritima

Zones:

Annual up to Zone 8; perennial in Zones 9-11.

Height/Spread:

Mounding habit, with plants reaching 4-6 inches tall and 10-12 inches wide.

Exposure:

Full sun to partial shade

Bloom Time:

Spring to fall

Color:

Purple, fading to pale lavender and white on top

One of the most common varieties, this dwarf form is readily available as seed or starts. Great for small spaces, between pavers or as edging.

ALYSSUM LANDSCAPING TIPS

There are many ways to incorporate this versatile annual into any landscape. Here’s how:

  • Place a hanging basket near your home’s entrance or next to the patio or deck where the sweet fragrance can be enjoyed up close.
  • Sow seeds in between rows in the vegetable plot to help suppress weeds and attract insects that are essential for crop pollination.
  • Plant as a ground cover around roses for a season-long carpet of color.
  • Combine white sweet alyssum with red salvia and blue ageratum for a July 4th patriotic theme.
  • Showcase in a rock garden with columbine, creeping thyme and sedums.
  • Broadcast seed or use plant starts to fill in gaps in a perennial border.
  • Plant along rock walls and allow plants to spill over the side for a romantic, cottage-style effect.
  • Add white varieties in a moon garden to illuminate pathways at night.

Sweet alyssum combines well with many other plants, such as nemesia, pansies, stock, geraniums, salvia, catmint, sedums and roses.

RELATED:
Annual Flowers
Planting Ideas

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