Alyssum Companion Plants for a Thriving Garden

Sweet Alyssum (Lobularia maritima) is a low-growing annual known for its profuse, honey-scented blooms. Often used as a fragrant edging for garden beds or as a spiller in containers, its thoughtful placement can also benefit neighboring plants, creating a more balanced and vibrant garden.

Benefits of Companion Planting with Alyssum

Alyssum attracts many beneficial insects. Its tiny flowers are a nectar source for adult hoverflies (syrphid flies), whose larvae are voracious predators of soft-bodied pests like aphids. By providing this food source, alyssum helps establish a local population of these helpful predators.

Alyssum also draws in tiny parasitic wasps, which are harmless to humans. These wasps lay their eggs inside pests like caterpillars and aphids, and the larvae consume the host from within. The plant’s blooms also support generalist pollinators like small native bees and butterflies, benefiting nearby fruiting plants.

The plant’s dense, spreading growth habit acts as a living mulch. This foliage shades the soil, suppressing weed germination by blocking sunlight. It also keeps the soil cooler and reduces water evaporation, conserving moisture for neighboring plants and protecting their roots.

Flower Companions for Alyssum

Alyssum is a functional and beautiful partner for roses. Planted at their base, its pest-attracting qualities help control aphids that trouble roses. The low, mounding habit also conceals the bare lower stems of rose bushes, creating a fuller look.

Snapdragons provide a striking contrast in height and form to alyssum. Their tall, elegant spires rise above alyssum’s spreading carpet, creating a multi-level display. Both plants thrive in full sun and have similar water needs, making their care straightforward in garden beds or large containers.

Planting marigolds with alyssum creates a layered defense system against pests. Marigolds are reputed to deter certain soil-dwelling pests, while alyssum attracts predatory insects that work above ground. The bright colors of marigolds also contrast vividly with alyssum’s white or pastel shades.

Petunias and alyssum are a popular pairing for containers and hanging baskets. They share similar needs for moisture and sun, and their growth habits are compatible. The mounding or trailing nature of petunias blends with the frothy texture of alyssum for a lush, overflowing look.

Vegetable and Herb Companions for Alyssum

Interplanting alyssum with leafy greens like lettuce and spinach keeps the soil cool, which can delay bolting as temperatures rise. Its ability to attract aphid predators also helps protect the tender greens from infestations.

Brassicas like broccoli, cabbage, and kale are susceptible to aphids. Planting alyssum nearby attracts hoverflies, which lay their eggs close to aphid colonies on these vegetables. This strategy helps manage pests on these plants throughout the growing season.

Tomatoes benefit from alyssum’s ability to attract a wide variety of pollinators, which can lead to more successful pollination and a better fruit set. As a ground cover, alyssum also helps retain the soil moisture that thirsty tomato plants require.

For root vegetables like potatoes, alyssum’s living mulch properties are beneficial. It suppresses weeds around the base of the plants, reducing competition for water and nutrients without disturbing developing tubers. This can lead to a more productive harvest with less manual weeding.

Plants to Avoid Pairing with Alyssum

Avoid planting alyssum with species that have conflicting water needs. Alyssum thrives with consistent moisture and should not be paired with plants adapted to dry conditions. For example, succulents like sedums or herbs like lavender prefer soil that dries out and can develop root rot in the moist conditions alyssum requires.

Alyssum’s light requirements must also be considered. It blooms best in full to partial sun and needs several hours of direct light to maintain its dense form. Avoid pairing it with deep-shade plants like hostas and ferns, as alyssum will become thin and leggy with few flowers in shady locations.

Avoid planting alyssum next to aggressive or fast-spreading ground covers. Vigorous plants like mint or periwinkle (Vinca minor) can easily outcompete alyssum for space, light, and nutrients, smothering the more delicate plant and preventing it from establishing.