Taylor Mauch, graduate student
Ajay Nair, associate professor
Department of Horticulture
nairajay@iastate.edu
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| Sweet Alyssum being grown in the field. |
Sweet Alyssum (Lobularia maritima) is a flowering annual or short-lived perennial of the family Brassiceae (mustard). It is native to the regions of the Mediterranean, Canary Islands, and Azores. It is grown as an annual in USDA zones 5-8 and a short-lived perennial in zones 9-11 in the United States. Its blooms are colored with white, pink, and purple flowers. Flowers are edible and non-toxic to humans and animals.
Sweet Alyssum is grown not only for the draw of its flowers in hanging pots and as a carpeting plant but also for its ability to attract beneficial insects in the field such as ladybugs and hoverfly. These insects are beneficial to plants as they feed on pests. Pests are considered to be unwanted insects that feed on crops and lower their economic viability. This can appear as insect damage on otherwise marketable crops. Sweet alyssum flowers attract beneficial insects which then move on to other plants in the vicinity. Having sweet alyssum as a food source could help to enlarge beneficial insect populations, providing more opportunity for these beneficial insects to attack pests. A classic example is aphid management using ladybugs. Most ladybugs found on crops and in gardens are aphid predators. Some species prefer only certain aphid species while others will attack many aphid species on a variety of crops. The ladybug can consume as many as 50 aphids per day as an adult. Seven spotted lady beetle adults may consume several hundred aphids per day and each larva eats 200 to 300 aphids as it grows. Therefore, Sweet Alyssum can be planted in guard rows or as bordering plants to help prevent infestations from pests, especially aphids.
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| Image 2. Insect damage on bell pepper. |
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| Image 3. An otherwise marketable bell pepper. |
The mature size of sweet alyssum plant is 3-9 inches tall and 10-48 inches wide depending on variety and does best in full sun to partial shade, though prefers shade from afternoon sun in warmer climates. It prefers moist but well drained soil and neutral to acidic soil pH. The bloom time is in the spring and goes until fall which allows for a longer window for attracting beneficials. Older cultivars of sweet alyssum can self-sow in temperate climates and are much more cold hardy than newer hybrids. Another benefit of them is that they are more drought tolerant. Though this is true, the newer hybrids have other advantages such as extreme vigor which causes them to grow much larger. The newer cultivars bloom all summer with no mid-season lull that is characteristic of older cultivars. The blooms are full during this time, but they are less drought tolerant than older cultivars.
When planting, seed can be broadcast in well-amended soil without any cover as light will aid in germination, which will occur in 7-20 days. Transplants can also be grown in the greenhouse or similar setting in flats several weeks before the latest average frost date. Be sure to keep plants well-watered without overwatering with fertilization occurring with a time-release fertilizer at planting then monthly after blooms are spent. No pruning is necessary. Sweet alyssum could be transplanted as an entire row between cash crop rows or could be planted within the cash crop row.