Rosemary shrubs help control harmful insect pests in the garden.
Use of toxic pesticides can be avoided by choosing insect- and disease-resistant shrub cultivars, according to Virginia Tech Cooperative Extension. Gardeners can choose native shrubs for their ability to attract birds and butterflies as well as repel species of spiders and bugs that are harmful to their growth. Some shrubs also attract beneficial insects to the garden. There are many such shrubs from which to choose. Does this Spark an idea?
Green Alder
Green alder (Alnus viridis) shrubs repel the spider mite, an insect that damages plant tissue by sucking its chlorophyll from leaves and stems. Spider mites cause dried-out leaves with yellow or red spots and blotches. Their fine, dusty-looking webs can be seen between leaves. Green alder shrubs have smooth, gray bark, shiny green oval-shaped leaves, and flowering catkins that appear in spring. Green alder grows rapidly and does well in poor soils.
Artemisia
The genus Artemisia belongs to the daisy family of plants, with 200 to 400 species of herbs and shrubs. Mugwort, sagebrush and wormwood are several of its well-known insect-repellent varieties. Wormwood is native to the Sierra Nevada, Rocky Mountain and Cascade mountain ranges of North America. Wormwood and other Artemisia cultivars are used in home gardens as a general insect repellent. Many Artemisia species have fernlike leaves that produce bug-repelling volatile oils.
Sage
Sage (Salvia) species that repel black flea beetle bugs include California native Cleveland sage, white sage, Black Island sage and desert sage. The evergreen, woody perennial shrub grows 3 to 4 feet in height. Culinary sage is a low-growing herb variety. Sage also attracts beneficial insects to the garden, including bees and butterflies. Cabbage moths are deterred from vegetable gardens when sage is planted nearby.
Rosemary
Rosemary (Rosmarinus officinalis) shrubs grow year-round in warmer climates and are used as houseplants where winters are more severe. The evergreen woody perennial grows to 5 feet in height when used as a shrub. Its strong fragrance and volatile oils repel harmful insects such as cabbage moths, bean beetles and carrot flies. Rosemary also provides habitat for common garden spiders that keep harmful insects under control.
Tags: Green alder, beneficial insects, beneficial insects garden, evergreen woody, evergreen woody perennial