Marigolds (Tagetes spp.) Are hardy, bright small flowers grown for their non invasive blooming. Marigolds come in hundreds of varieties. Some species are also beneficial: French marigolds (Tagetes patula) secrete a substance from their roots which kills nematodes and repels whiteflies. But all insects will not repel out of your own herbs.
Herbs and Pests
Herbs are resistant to pests and diseases. Their strong odor keeps many pests away, as well as those bugs which do bother the plants seldom seriously damage them. However, herbs are not completely pest-free: Aphids, spider mites and whiteflies all commonly infest herbs. And although marigolds might repel whiteflies, they will not repel aphids or spider mites; both of which can infest herbs grown inside and outside.
Plant Them Anyway
Marigolds may not repel all insects which come near your herbs, but they are still beneficial. Hardy in U.S. Department of Agriculture plant hardiness zones 9 through 11, you can treat them as annuals in cooler climates. French marigolds kill nematodes and blossom continuously until frost. Small and bushy, they don’t usually grow taller than 12 inches and make an attractive edge and contrast for your herb garden without overpowering the herb plants. Marigolds thrive in full sun and adapt to all kinds of soil as long as they are watered during times of drought.
Be , Bugs
You’ll likely have to take different steps to eliminate pests in your herbs. The easiest way to do this is to blast them off with a solid flow of water. This has the additional benefits of rinsing the leaves off of your herbs and additionally watering them. You can even remove aphids, spider mites and mealybugs off the plants by dipping a gentle brush into a solution of 2 teaspoons of mild liquid detergent added to 1 gallon of water. Or, make an all-natural pesticide — one which will not harm your herbs or cover them with chemicals — by adding 15 garlic cloves and one pint of water into a blender. Puree until it’s smooth, and then strain it through a piece of cheesecloth. Pour the mix into a spray bottle and thoroughly coat the top and bottom of the leaves of infested plants.
Other Alternatives
It is not just marigolds that can repel specific insects in the own herbs. Petunias (Petunia spp.) , which increase as perennials in USDA zones 10 through 11, but are often treated as annuals, repel various types of aphids and other insect pests. They thrive in full sun and light color and, like marigolds, petunias will bloom all summer when cared for properly. Dill (Anethum graveolens) is useful in the kitchen and repels aphids and spider mites. This yearly herb thrives in full sun and in well-draining soil and has the added plus of being deer-resistant.