Annual
Sweet Alyssum
Lobularia maritima · Brassicaceae
Also called: Sweet alyssum, Sweet alison, Carpet flower
Sweet Alyssum (Lobularia maritima) is a low-water annual well suited to Tucson and the low desert. It's a fast-growing annual.
Sweet Alyssum at a glance
- Water use
- Low (established)
- Sun
- Full sun in the cool season; light afternoon shade helps it persist into warm spring.
- Mature size
- 3–8 in tall, 8–14 in spread (low, spreading mounds).
- Growth rate
- Fast
- Bloom
- White (most common), plus pink, lavender, purple, and apricot cultivars., Winter through spring (Nov–Apr/May); can rebloom from self-sown seed in favorable spots.
- Cold hardiness
- Half-hardy; tolerates light frost (to roughly mid-20s°F). Cool-season plant — fades in summer heat, though it may persist longer in shaded, irrigated microclimates.
- Soil
- Well-drained soil; adaptable and tolerant of poor and alkaline desert soils. Good drainage is the main requirement.
- Native range
- Mediterranean region; naturalized in many warm climates including parts of the western U.S.
- Best used as
- Low edging and bed fronts, Spilling over container and basket edges, Groundcover-style filler between taller annuals, Fragrant honey-scented sweeps, Beneficial-insect/pollinator habitat
- Wildlife
- Excellent nectar source — attracts bees, hover/syrphid flies, and other beneficial insects (useful for vegetable-garden pest control).
- Toxicity
- Non-toxic to people, dogs, and cats.
How to grow Sweet Alyssum in Tucson & the low desert
Watering
Cool-season annual in Tucson — sow seed or set transplants Oct–Nov for winter-spring carpets of bloom. Lower water needs than pansies/stock once established; water 1–2x/week, keeping soil lightly moist. Often self-sows. Declines in heat (late spring).
Fertilizer & nutrients
Light feeder — compost-amended soil is usually enough. A diluted balanced fertilizer once or twice during the season is plenty; avoid excess nitrogen, which reduces flowering.
Pruning & care
Shear back by about one-third after the first heavy flush to rejuvenate and trigger reblooming; otherwise low-maintenance.
Notes
Honey-scented, fast and easy from seed. A top filler/edger for Tucson winter beds and containers. Frequently reseeds. Member of the mustard family. Use as a living mulch and pollinator magnet alongside cool-season vegetables.
Sources: University of Arizona Cooperative Extension – Pima County cool-season planting guides; Missouri Botanical Garden Plant Finder; AMWUA Landscape Plants for the Arizona Desert