If you work hard to create a thriving, attractive landscape, it can feel especially frustrating when insects damage your plants or make it miserable to spend time outside. Before you reach for harsh, side-effect-laden chemical pesticides, try bug-repellent plants in your borders. Whether through toxic chemicals or strong scents, certain plant species deter pests, while other species attract pests away from more valuable plants. Fill your borders with these resistant or repellant species for safe and attractive pest control.
Strongly scented plants, such as garlic (Allium spp.), rue (Ruta graveolens) and tansy (Tanacetum vulgare) repel Japanese beetles. These destructive bugs are attracted to knotweed (Polygonum spp.), a perennial flower that blooms with red, pink and white flowers from summer through fall. Plant a border of knotweed to attract beetles away from other plants.
To repel aphids, choose pungent species, including garlic, basil (Ocimum basilicum), chives (Allium schoenoprasum), coriander (Coriandrum sativum), dill (Anethum graveolens) and petunias (Petunia x hybrida). Aphids are drawn to nasturtiums (Tropaeolum majus) and feverfew (Tanacetum parthenium); plant a border of these annuals to draw the pests away from other plants.
Whiteflies feed on foliage, leaving behind a sticky substance that then grows black mold. Repel these pests with a border of marigolds (Tagetes spp.), nasturtiums, tansy and basil.
Tomato hornworms, large, bright-green caterpillars that feed on tomato foliage, are deterred by strongly scented plants. Plant a border of basil, borage (Borago officinalis), calendula (Calendula officinalis) and marigolds to repel these destructive insects.
Nematodes, microscopic worms that live in the soil, feed on plant roots and cause a great deal of damage. They are repelled by marigolds, dahlias (Dahlia spp.) and chives.
Cabbage Worms and Butterflies
As their name suggests, both the larvae and adult forms of these insects are attracted to plants in the cabbage family. To keep them away, plant a border containing scented herbs including mint (Mentha spp.), oregano (Origanum vulgare), thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), sage (Salvia spp.), dill, chamomile (Chamaemelum nobile) and lavender (Lavendula angustifolia). They are also repelled by hot pepper plants (Capsicum spp.), geranium (Pelargonium spp.), hyssop (Hyssopus officinalis) and nasturtiums.
While they may not damage your landscape plants, mosquitoes irritate humans, and some carry disease. Certain plants contain oils and scents that repel mosquitoes. Lemon grass (Cymbopogan nardus) grows as a decorative grass and contains mosquito-deterring essential oils, as does a geranium-citronella grass cross called Vanieeni or citrosa (Pelargonium citrosum “Vanieenii”), which repels mosquitoes with its citrus aroma. Lemon thyme (Thymus x citriodorus) also has a citrusy, mosquito-repelling scent. However, these plants work best when their leaves are crushed to release fragrance.
- Iowa State University: Mosquito Repellent Plants
- Colorado State University Extension: Plants Help Keep Mosquitoes Away
- Alabama Cooperative Extension System:
- Brandeis University: Insect Repellent
- Brigham Young University: Companion Planting Guide
- Cornell University: Companion Planting
- Alabama Cooperative Extension System: Companion Plants
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