10 Herbs You Can Use as Pesticides in Your Sustainable Gardening

For any sustainable garden, herbs are the spice of life. They can turn an otherwise bland meal into a savory dish you’ll never forget. When they’re not adding a tangy kick to your favorite entrées, you can brew them to make teas or pour them into a diffuser for aromatherapy. 

But your favorite herbs can do more than satisfy your senses. Herbs can also protect your garden from pests. The six-legged creatures that enjoy nibbling your crops will meet their kryptonite when they come in close contact with these herbs. 

This post will take a look at ten edible herbs that can defend your garden against destructive bugs. 

1. Alliums

The name allium sounds like an element on the periodic table, but it’s a scientific term for household herbs, including garlic, chives and our favorite tear-jerkers, onions. Chives and onions are especially useful as natural pest control agents. Chives and onions can deter a wide range of bugs, including spider mites, carrot flies and aphids. 

Alliums ward off damaging insects just as effectively as chemical pesticides without the risk of soil contamination. They’re a win-win for your garden, not to mention your health. 

2. Basil

Have you ever smelled cologne or perfume that was pleasant to you but off-putting to someone else? Basil is nature’s equivalent of such a fragrance. 

This herb’s poignant aroma is an olfactory delight to humans but a strong deterrent for various pests. It shoos away troublesome critters, including whiteflies, carrot flies, asparagus beetles and even mosquitoes. 

One of the virtues of basil is its ability to thrive almost anywhere. You can plant the herb near benches, hammocks, patios or any outdoor furniture. Basil not only tastes and smells great, but it will also allow you to enjoy your garden without having to swat flying pests. Plus, you can make some great pesto whenever you wish!

3. Bay Leaf

Bay leaves can be a standard fixture in cuisines from the Mediterranean, Latin American and the Caribbean. They’re used to season various soups, stews, and sauces. However, the bay leaf has a different use that you wouldn’t find on a store-bought package – it is a potent pesticide. 

It can repel common invaders such as flies, ants, cockroaches and more. You don’t need to expend much effort when using bay leaves for pest control purposes. Just sprinkle bits and pieces of the leaves throughout infested areas, and voila! Those notorious Invaders will get the memo not to come back. (The plant bay leaves come from Sweet Bay or Laurus nobilis is a warmer season plant, so you may have to grow in a container in Tennessee and bring in during hard freezes)

4. Cilantro

It’s true what they say about cilantro – you either love it or hate it! Scientific research has even identified genes that influence whether people enjoy or despise its flavor. With that said, some species of insects share a common ground with the folks who hate cilantro. 

Aphids, spider mites and Colorado potato beetles, in particular, can’t tolerate this herb and will stay far, far away if it’s in your garden. So, if you’re dealing with an invasion of these bugs, consider planting cilantro as a pest control agent. Whether you eat it or not is up to you.

5. Chrysanthemums

Chrysanthemums are native to the Mediterranean, but East Asian cultures make the most extensive use of them. The Chinese, Japanese, and Korean populations use the herb to season various dishes and benefit from its mineral and vitamin-rich profile. 

It’s also a powerful bug neutralizer. Chrysanthemums repel a wide range of critters, including spider mites, silverfish, Japanese beetles, bed bugs, roaches, fleas and ants. This exotic herb also blooms in a burst of bright color, making it a welcomed addition to your garden.

6. Dill

Rich in flavor, aroma, and antioxidants, dill is a herb you should consider cultivating. Not only does it infuse a savory taste in meat or vegetable dishes, but it also repels bugs that you do not want anywhere near your garden. That includes the likes of spider mites, squash bugs and aphids. 

There is one caveat with dill: they attract tomato hornworms, and they will eat your tomato plants if you have them. So, if you’re going to cultivate dill, make sure that you plant them away from your tomatoes.

7. Lavender

Lavender, it’s far more versatile than you realize. The flowers are colorful, aromatic and even useful in cooking. It’s a mint family member, including rosemary, sage and thyme, and chefs worldwide use it to elevate food flavor and appearance. 

But lavender is also an effective natural pesticide. Its sweet scent is a nightmare for pests such as carrot rust flies, cabbage moths, and bean beetles. If you haven’t added lavender to your “To Grow” list, do so now! They provide a splash of color to your flower bed, a dash of flavor to your favorite cuisine, and a lash of menace to your garden’s invaders. An excellent variety for Tennessee is “Phenomenal” lavender. Try growing it on a bit of a mound in full sun for best results.

8. Mint

Mint hardly needs an introduction, and you can use its leaves for just about anything. The herb is renowned for its medicinal powers, alleviating digestive upsets, respiratory ailments and more. And who doesn’t enjoy a cup of hot mint tea in the winter! 

What gardeners overlook mint for, though, is its role as a natural pesticide. It keeps aphids, fleas, beetles, cabbage moths and ants out of your garden.

Just one note of caution with mint plants: they can be invasive and grow all over your garden if you’re not too watchful. That’s why it’s wise to grow mint in pots, so they don’t get too unruly.

9. Nasturtiums

Nasturtium may be foreign to the average homeowner, but seasoned gardeners enjoy cultivating these vibrant flowering plants. Not only are they edible (their spicey flowers are great on salads or just a good nibble as you’re working in the garden), but they’re also a useful trap crop since the mustard oil they release repel common pests. The colorful leaves of a nasturtium repel pests such as aphids and whiteflies.

10. Wormwood

Wormwood has gotten a bad rap. It has historically been used to flavor the alcoholic beverage absinthe, a drink purported to cause hallucinations (due to wormwood’s thujone content). However, this is just a myth, with its reputation for hallucinatory factors emerging from a smear campaign.

Wormwood can also serve as your secret weapon against garden pests. Wormwood repels cabbage worms, slugs, carrot rust flies, black flea beetles, and white cabbage butterflies, all of which can seriously harm your crops. 

On a side note, there are hundreds of species of wormwood plants, many of which make beautiful ornaments for your garden. If you’re worried about thujone, don’t be. You don’t need to eat the plants.

An Herbal Twist for Ecological Landscape Design in Knoxville

The herbs you grow (or buy) to season your favorite dishes are some of nature’s most powerful, reliable and safest natural pesticides. They also support your sustainable gardening efforts, as they are an eco-friendly alternative to harmful chemical pesticides. 

Once cultivated, you can make fewer trips to the produce section at the grocery store and skip past the spray-bottle pesticides altogether. 

Landscape Architecture for Practicing Sustainable Gardening

If you’re looking for more natural pest control options, stay tuned for our following post on DIY pest control traps, including my latest posts on beneficial insects to keep your pest problem at bay.

Are you looking for help embedding these sustainable gardening practices in Knoxville or East Tennessee? A trusted landscape architect can help with native plants, rain barrels to conserve water, or ways to minimize garden waste. Contact me today.