Alisons (genus Alyssum) are flowering plants native to the Mediterranean, Europe, northern Africa, and Asia. There are nearly two hundred plants in the genus, and two species formerly in the genus – sweet alyssum (Lobularia maritima) and gold tuft alyssum (Aurinia saxatilis) – are closely related and still colloquially grouped. Other floral relatives of alisons include the cabbage and mustard plants.
Interestingly, the word alyssum is derived from an ancient Greek term meaning “without madness.” Why? In ancient times, the plant was used to treat the bites of rabid animals.
Appearance
Alisons are low growing plants that often form mounds, typically one foot high and one foot in diameter. Some are considered “sub-shrubs,” shrub-like in appearance but generally smaller than true shrubs. Alisons produce clusters of tiny flowers, in shades of pink, purple, white, and yellow. The small, pointed evergreen leaves of some varieties make this plant interesting to look upon, year round.
Environment
Wild alisons typically inhabit areas of thin, rocky soil, such as coastal areas. Weather is often hot and dry, making the plant well suited to the contemporary drought garden. In warmer climates, many species have a perennial growing habit. When considering other varieties, and in colder climates, remember that the alison must be replanted yearly, as an annual.
Varieties
Hundreds of types of alisons exist, but only a few will be readily found at your local garden center. These include, but are not limited to:
“Roseum” is an alison described as a mounding sub-shrub with silvery leaves and small pink flowers. This plant’s beauty and versatility earned it the Royal Horticultural Society’s Award of Garden Merit.
“Snow Princess” produces white flowers, as its name suggests. This variety is very tolerant of extremely hot or cold temperatures, but also requires additional watering during the summer months.
“Crystal Clear Lavender” is one of the larger cultivars, spanning more than a foot in diameter. Flowers are purple.
Yellow alyssum, also called pale madwort, has small yellow flowers that fade to white with age.Yellow alyssum is considered an annual or biennial, meaning it blooms in its second year of growth, and after blooming, it dies. This plant now grows “wild” in many temperate zones, having been an introduced species.
Alyssum desertorum is native to Europe but grows in North America as an introduced species. It is an annual and produces small, yellow flowers.
Basket-of-gold, or golden tuft alyssum, has silvery leaves and overflows with clusters of yellow flowers. It is a favorite in rock gardens.
Care
Plant in full sun. You may purchase adult plants from a garden center or start from seed. Alisons can be grown in all USDA planting zones, but cultivation may differ depending on climate. Some types of alison are perennial, whereas others must be replanted annually. Perennial varieties typically do not have as long a lifespan as other perennial plants. All alisons act as annuals in colder regions. Non-hybrid types will self-seed, emerging from the soil as “volunteers” in the spring.
Alisons thrive in well drained soil, but must be watered during the hottest parts of summer. If your alisons become dry and die back early, you may be able to revive the plant. Cut back the foliage by one third and water thoroughly and often until the plant recovers.
Benefits
Alisons can thrive in environments less hospitable to other plants, including rock gardens. They do well as container plants, including hanging baskets. They may also be used to enliven retaining walls, trailing and tumbling from the top. There low growing nature and tolerance of thin soils make them an ideal choice for erosion control.
When in bloom, alisons emit a smell similar to honey. Alisons are fed upon by the caterpillars of certain butterfly species, making them ideal for a butterfly gardens. Rabbits refuse to eat the plant, allowing it to persist in gardens frequented by these small mammals.
Quick Facts
Height: 1 foot
Lifespan: Annuals or evergreen perennials
Flowers: Small bunched flowers, each with four petals; yellow, white, pink, or purple in color
Seeds: Small rounded seed pods; silicles
Leaves: Small and lance-shaped, untoothed, with silver hairs
Regions: All
Genus: Alyssum
Species: A. spinosum, A. alyssoides, A. desertorum, A. saxatilis,
L. maritima
Resources
“Alysum.” Wikipedia.
“Alyssum alyssoides.” Wikipedia.
“Alyssum desertorum.” Wikipedia.
“Basket-of-Gold, Plant.” Encyclopaedia Britannica.
Hattatt, Lance. Encyclopedia of Garden Plants and Flowers. 1998.
Machucho, Megan. “Sweet Alyssum: How to Grow and Care for This Flowering Ground Cover.” Dengarden.
“Sweet Alyssum, Plant.” Encyclopaedia Britannica.