How to Plant, Grow, and Care for Alyssum

Alyssum is a popular, low-growing annual recognized for its delicate flower clusters and sweet, honey-like fragrance. Its reputation as an easy-to-grow plant makes it a favorite for gardeners of all experience levels. This plant offers versatility in garden design, adapting to various roles within a landscape.

How to Plant and Grow Alyssum

When to Plant

It is best to plant alyssum after the danger of frost has passed in the spring. Alyssum seedlings have some tolerance for light frost, but freezing temperatures can be damaging. Sowing can occur from early spring into early summer. In regions with mild winters, planting can also take place in the autumn.

Light

Sweet alyssum grows well in full sun, which promotes the best flowering, but it can also tolerate partial shade. In areas with intense summer heat, planting it in a location that receives afternoon shade is beneficial. Ideally, the plant should receive about six to eight hours of sunlight daily. This helps prevent the plant from drying out too quickly.

Soil

The plant requires well-draining soil to prevent issues like root rot. It is adaptable to various soil types, including sandy and less fertile soils. The plant’s ability to grow in diverse locations, such as in the cracks of sidewalks or on slopes, highlights its preference for drainage. A soil pH between 6.5 and 7.0 is suitable.

Water

Provide at least an inch of water each week after planting to help the root system develop. Once established, its water needs are moderate, though more frequent watering is necessary during particularly hot or dry spells. Good drainage remains important, as alyssum does not perform well in boggy or waterlogged soil.

Fertilizer

Alyssum is not a heavy feeder and performs well without supplemental fertilizer if the soil is reasonably fertile. If the soil is poor, a controlled-release fertilizer can be applied at planting time. For plants in containers, a water-soluble fertilizer applied monthly can be beneficial. In garden beds, mulching with compost before planting can encourage healthy growth.

Ongoing Care and Maintenance

Once established, alyssum requires minimal care to maintain its appearance and vigor. The primary maintenance task involves shearing the plant during mid-summer when it can become leggy and flowering may decrease. This process is straightforward and yields significant results for the plant’s health.

Cutting the plant back by about one-third to one-half encourages a fresh, compact flush of new growth. This trim revitalizes the plant, stimulating a second wave of blooms that can extend its flowering season into autumn. A quick shearing is a more efficient method than deadheading to ensure alyssum remains a dense, flower-covered mat until the first hard frost.

Landscaping with Alyssum

Alyssum’s low, spreading habit makes it an excellent edging plant, creating soft, fragrant borders along walkways, patios, and the front of garden beds. Its dense flowers form a living ribbon of color that neatly defines garden spaces.

In container gardening, alyssum excels as a “spiller” plant. When placed in hanging baskets or mixed pots, its trailing stems cascade over the edges, softening the lines of the container and filling in gaps between taller plants.

It also functions as a fast-growing ground cover, filling bare soil between new perennials or shrubs to suppress weeds. Alyssum is also known for attracting beneficial insects, including tiny wasps and other pollinators, which can help with pest control in vegetable gardens.

Common Pests and Diseases

Aphids are a potential pest that can be managed with simple, non-chemical methods. A strong spray of water from a hose is often sufficient to dislodge these insects from the plants.

The most significant health risk to alyssum is root rot, which is a fungal issue resulting from improper growing conditions. Overwatering or planting in soil with poor drainage creates an environment where these problems can develop. Ensuring well-draining soil from the start is the best prevention.