March 20, 2023

Extension Notebook: Fortify the spring vegetable garden with marigolds, sweet alyssum and nasturtiums

Fight nature with nature

In late spring, a gardener walks out to their vegetable garden ready to collect one of the first harvests of the season, only to discover shot holes through kale and bites taken out of cabbages — even the tomatoes suffered, with many plants nursing broken stems. As the gardener returns to the kitchen, excitement for the morning harvest ends in disappointment.

Many vegetable gardeners and farmers alike experience the disappointment of pests pillaging a garden. Deer and rabbits consume tops off fruiting vegetables, while cabbage loopers, aphids, and flea beetles chew holes in plant leaves. Perhaps accepting the reality of pests, some growers commit extra resources annually to their production by planting an overabundance of crops, to mitigate their losses. Another option is to combat pests by fighting nature with nature. By planting marigolds, sweet alyssums, and nasturtiums in strategic locations, vegetable growers big and small can lessen crop damage, create a beneficial insect refuge, and grow a greater diversity of food.


Marigolds (Tagetes spp.) are both beautiful and strongly scented. In fact, the plant’s pungent aroma can deter mammals. According to the University of Minnesota Extension, their distinct odor can make them and neighboring vegetables unappealing to deer and rabbits, even in spring, when flowers are not present. The added color that comes to the garden from marigold is a bonus. There are an array of vibrant colors to choose from when purchasing seeds or transplants, with the most popular colors being red, orange, and yellow. Yet another benefit that comes from the growing of marigolds in the garden is a feeling of nostalgia for those whose parents had them in their garden. Nothing smells quite like mid-summer than marigolds. Beautify the garden, ward off the grazers, and smell the family memories by planting marigolds.

Sweet Alyssum

Sweet alyssum (Lobularia maritima) is a flowering, short-lived perennial of the mustard family. It prefers moist yet well-drained soils and can grow in full sun to partial shade, making it a versatile choice for many growing areas. Sweet Alyssum, a carpeting plant, attracts beneficial insects, like hoverflies and ladybugs, with small, sweetly scented flowers. These insects are miniature cavalry in the garden — attacking insect pests that eat vegetables. Sweet Alyssum is so good at attracting and hosting beneficial predatory insects that it is added throughout the greenhouses on the campus of the University of Illinois at Urbana-Champaign. As added evidence of Sweet Alyssum’s power, Iowa State University Extension reports, some species of adult ladybugs that are harbored by this plant can consume as many as several hundred aphids per day. Plant Sweet Alyssum as a border plant around the garden to prevent aphid infestations.


Nasturtium (Tropaeolum majus) is an easy-to-grow plant that adds unique color and shape to the garden with intensely hued flowers and round flat leaves that are reminiscent of lily pads on a pond. It is native to sub-tropical parts of Central and South America and will attract pollinators, like hummingbirds and honeybees which increases pollination rates, according to the New Jersey Agricultural Experiment Station at Rutgers University. Though they do not ward off pests, nasturtium leaves and flowers are edible — adding a pleasantly spicy and flavorful taste to salads. When planted in dappled shade of foliage-dense sunflowers, tomatoes, or peppers, nasturtiums have been known to prosper. Plant trailing or compact varieties throughout the garden to benefit both you and local pollinators.

Now, a new future is possible. It is mid-summer, and the vegetable garden looks superb. The deep green of vegetable foliage and light green of developing crop fruits are contrasted with three companion plant species: red and yellow marigolds, white Sweet Alyssums, and orange nasturtiums. Pollinators, busy with their incredible work, fly in and out, foraging among the sources of scent and color. What is missing from this glorious picture? Major crop damage by pests, and that is all by design.


Marigolds – University of Minnesota Extension,

Sweet Alyssum to Attract Beneficials – Iowa State University,

Nasturtium – University of Maryland Extension,

Nasturtium, Tropaeolum majus – University of Wisconsin-Madison, Department of Horticulture,

Nick Frillman is a local food systems and small farms educator serving Livingston, McLean and Woodford counties for University of Illinois Extension.