Alyssum Identification Guide
Identify sweet alyssum (Lobularia maritima), a low, mounding garden annual with tiny four-petaled honey-scented white or purple flowers in dense clusters and narrow gray-green leaves. Includes look-alike comparisons.
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Key Identifying Features
Sweet alyssum (Lobularia maritima) is a low, spreading, much-branched plant grown as an annual, famous for its carpets of tiny honey-scented flowers. Identify it by the dense rounded clusters of small four-petaled white (or pink/purple) flowers, its narrow gray-green leaves, and its sweet fragrance, all on a compact mounding or trailing plant just a few inches high.
- Low, mounding or trailing habit, 3 to 8 inches tall
- Dense, rounded clusters of many tiny flowers
- Four petals per flower (a mustard-family cross)
- Honey-sweet scent
- Narrow, soft, grayish-green leaves
Leaves & Stems
The leaves are small, narrow, lance-shaped to linear, untoothed, and grayish-green, often with fine appressed hairs that give a slightly silvery look. They are alternate along slender, many-branched stems that spread outward and root lightly to form a low cushion or mat. The whole plant is soft and bushy, rarely exceeding a hand's height, and quickly fills gaps in borders, edging, and containers.
Flowers & Fruit
Each flower is tiny (about 0.2 inch) with four petals arranged in a cross, the classic shape of the mustard family (Brassicaceae). Flowers crowd into dense, dome-shaped clusters (racemes) that lengthen as they bloom. The most common color is pure white, but cultivated forms range through pink, lavender, rose, and deep purple. The flowers are strongly honey-scented and attract bees and hoverflies. Fruits are small rounded two-seeded pods (silicles). Sweet alyssum blooms profusely from spring through fall, often pausing in extreme heat.
How to Tell It Apart from Look-Alikes
- Candytuft (Iberis): Also a low mustard with white flower clusters, but its flower clusters are flatter and the outer petals are notably larger, and leaves are broader and dark green.
- Lobelia: Despite similar bedding use, lobelia has two-lipped (not four-petaled cross) flowers and is unrelated.
- Wild alyssums / hoary alyssum: Are taller, coarser weeds with yellow or smaller white flowers and a less sweet scent.
The blend of tiny four-petaled cross-shaped flowers in honey-scented domed clusters on a low gray-green mound points clearly to sweet alyssum.
Where You'll Find It
Sweet alyssum is grown worldwide in gardens, borders, edging, rock gardens, hanging baskets, and containers, and it readily self-seeds. Native to the Mediterranean, it naturalizes along coastal dunes, roadsides, and disturbed sunny ground in mild climates, tolerating sandy, well-drained soil and salt spray.
Quick ID Checklist
- Low mounding/trailing plant, 3 to 8 in
- Tiny four-petaled flowers in domed clusters
- White, pink, lavender, or purple
- Honey-sweet fragrance
- Narrow grayish-green leaves
- Small two-seeded pods; common in borders and containers
Frequently asked questions
How do I know a flower is in the mustard family like alyssum?
Look at a single flower under magnification: sweet alyssum has four petals arranged in a cross, the signature shape of the mustard family (Brassicaceae).
What does sweet alyssum smell like?
It has a distinctive sweet, honey-like fragrance that carries on the air, which is one of the easiest ways to recognize it in a garden.
How is alyssum different from candytuft?
Candytuft has flatter clusters with noticeably enlarged outer petals and broader dark green leaves, while sweet alyssum has uniform tiny flowers in domed clusters and narrow gray-green foliage.
Is alyssum only white?
No. While white is the classic color, cultivated forms also come in pink, rose, lavender, and deep purple, all with the same tiny four-petaled flowers and sweet scent.