Sometimes a flower does more than just add beauty to your garden. Pyrethrum daisies not only look beautiful when massed together, but also help keep bugs away from your plants.

Pyrethrum daisies are a source of chemical components known as pyrethins. The Mississippi State University Extension says pyrethins extracted from the plants were one of the first insecticides ever used. They're still popular today since they aren't harmful to mammals and won't harm bees visiting the flowers.

Pyrethins are impressively effective against a variety of insects. The Brooklyn Botanical Garden says insects exposed to them can be knocked down almost immediately. Pyrethins are also irritating enough to insects that they can be used as a way to disperse pests. The gardening company Park Seed says pyrethrum daisies are a good way to keep insects such as ants, flies, mosquitoes, and moths at bay.

The plant itself produces impressive blooms of flowers. The Cornell University Cooperative Extension says flowers will grow up to two-and-a-half feet tall, usually have yellow centers, and produce petals in shades of red, yellow, purple, pink, or white.

Pyrethrum daisies can be sown by seed, but will also transplant well. The plants can be divided in the spring or early fall.

When started from seed, you'll have to be patient. Park Seed says it will take two years for seeds to produce flowers.

Seeds can be planted outdoors in the spring or summer, as long as they are sown with at least two months before the anticipated first frost of the fall. They can also be started indoors at temperatures of about 55 degrees. The Cornell University Cooperative Extension recommends starting seeds indoors four to six weeks before the last frost of the spring.

When planting seeds outside, look for an area with full sunlight. Pyrethrum daisies will also grow well in partially shaded areas. However, Ecological Agriculture Projects of McGill University in Quebec says reduced sunlight will bring down pyrethrin concentrations, making the flowers less effective at repelling insects.

The perennial plant will thrive in a wide variety of climates, including USDA zones 3 through 7. Well-drained, gravelly soils with high concentrations of lime are ideal. The plant will also grow well in loamy soils rich in humus, but the pyrethrin concentrations will not be as high.

Seeds don't need to be covered by too much soil for germination to occur. Park Seed recommends planting them no deeper than four times the width of the seed. Space plants 12 inches apart.

Pyrethrum daisies require relatively minimal care. They should be watered regularly, and can be treated with a balanced fertilizer. Staking flowers may be necessary in windy, unprotected areas.

Cutting back the plant can help it to grow bushier and produce more flowers. The Cornell University Cooperative Extension says you can promote bushy growth by pinching off the developing leaves when the plant is about six to eight inches tall. Cut the stems after the first bloom to encourage the plant to flower a second time during the season.

Although pyrethrum daisies can serve as natural insecticides, they can still be vulnerable to certain pests. The Missouri Botanical Garden says aphids, leaf miners, nematodes, and spider mites can be a problem.

Pyrethrum daisies work well in a variety of areas, including borders and rock gardens. The colorful flowers will also look beautiful in bouquets.

Used flowers can also be used to help protect other plants in your garden. Ecological Agriculture Projects says you can repel insects by drying and crushing pyrethrum daisies, then adding the resulting powder to plant leaves. You can also soak dried flowers in about six liters of water for three hours, then use the water in a sprayer.