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Alyssum spp.
alyssum
Europe, Mediterranean, North Africa, central and western Asia
Overview
Alyssum spp. is a genus of roughly 100-170 species of low annuals, perennials, and small subshrubs in the cabbage family (Brassicaceae), native across Europe, the Mediterranean, and central and western Asia. Plants form low mats or cushions 2-12 in (5-30 cm) high, with small, grey-green, often star-haired leaves that give a silvery cast. Dense clusters of tiny four-petalled flowers, mostly yellow and in a few species white, open in spring above the foliage. Each flower is about 0.1-0.2 in (3-5 mm) across, and the massed bloom can hide the leaves. Flowers are followed by small rounded or oval flattened seed pods typical of the family. The genus grows on dry, rocky, and stony ground, screes, and limestone slopes, mostly in full sun. The white-flowered bedding plant sold as sweet alyssum belongs to the related genus Lobularia spp., not to Alyssum spp. itself. Perennial species are short-lived and decline in rich or wet soils, holding up on lean, sharply drained ground.
Native Range
The genus is native to Europe, the Mediterranean region, North Africa, and central and western Asia, with many species in Turkey and the Balkans. Plants grow on dry rocky slopes, screes, cliffs, and stony grassland, often over limestone.Suggested Uses
Grown in rock gardens, gravel gardens, wall crevices, and the front of dry borders for spring colour. The cushion habit suits troughs and the tops of retaining walls, and the early flowers draw bees.How to Identify
Appearance
Size & Dimensions
Height2" - 1'
Width/Spread6" - 1'6"
Colors
Bloom Information
Flowering comes in spring, roughly April to June, when the foliage is covered by dense heads of small yellow or white flowers. Bloom lasts several weeks and draws early bees. A light trim after flowering can prompt a lighter second flush in some species.
Detailed Descriptions
Flower Description
yellow, white in some speciesFoliage Description
grey-greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Plants grow in full sun and dry, gritty, sharply drained soils of low fertility, including chalk and rocky ground. Established plants are drought-tolerant and need little water once settled. Wet winter soil and high fertility cause soft growth and rot, the main limit on the perennial species. A trim after the spring flush keeps cushions dense and tidy. Plants are mostly short-lived and are renewed from seed or cuttings every few years. No routine feeding is needed on lean soils.Pruning
A light shearing right after the spring bloom removes spent flowers and keeps the cushion compact. Hard cuts into old bare wood of subshrubby species are slow to regrow, so trimming stays within recent growth.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
late spring
Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons