Plants that Naturally Repel Bugs
Slugs, aphids, emerald ash borers, mosquitos, tomato worms – There’s no shortage of garden pests here in Michigan. Some of the most common critters can be a real menace too. You need only find one or two of your hostas looking all torn up and forlorn – with their perforated, scraggly leaves drooping down into the dirt – before you start developing a real dislike for the common garden slug.
Similarly, while we’re sure that mosquitoes are an essential part of the food chain, we’d still prefer it if they didn’t flock to our gardens every time the sun starts to drop below the skyline!
Fortunately, there are safe (and cruelty-free) ways of keeping bugs and animals out of your garden. In fact, there’s a whole host of different herbs, flowers and bedding plants that are known to repel common garden pests, and a little strategic planting can help to ensure that your garden stays unblemished year-round.
Some of these plants are actually more effective than other, traditional, methods too. They keep pests at bay using astringent chemicals and natural toxins, and we’ve found that they tend to yield much better results than things like the eggshell trick, or citronella candles – which have proven ineffective in several scientific studies.
So, if you’re trying to keep bugs or animals out of your garden, this is the guide for you! Drawing on years of combined expertise, we’ve put together a full list of all the best natural deterrents, including favorites like yarrow, and some staples like ageratum.
French marigolds are a good, multi-purpose insect repellent. Their scent is known to discourage whiteflies and a number of other, airborne insects. several studies have shown that nematodes of many different types will try to avoid them. Some people do also report that French marigolds make for a good mosquito repellent but there is less evidence to support this.
Mexican marigolds are a different story entirely. They’re less effective at killing nematodes, but they are disliked by the vast majority of flying insects, so scattering them about the garden is probably a good first line of defense. There are also some rumors that Mexican marigolds can deter rabbits and other rodents, but we’re not sure we’d be confident relying on these (admittedly pretty) flowers for that.
Do take care when planting marigolds too – they’re a great way to repel airborne insects, but they do attract another pest: The dreaded slug. As such, we’d always recommend that you keep your marigolds away from any veggies that you want to keep slug-free, or companion plant with another natural slug repellent.
Speaking of slug repellents, rosemary is a fantastic plant that’s well-suited to repelling these ugly intruders. It’s thought that the tar-like substance that coat the plant’s trichomes are irritating to slugs, snails, and other land-borne insects, and planting a few bushes can help to clear up a border or bed quite quickly.
Rosemary does also produce a fragrant, woody scent that’s known to repel any flying insects with a sensitive nose (including mosquitoes, flies, moths and most beetles). The plant is native to the Mediterranean though, so it is quite challenging to grow it here in Michigan. Make sure it’s planted in well-draining, sandy soil, and make sure it’s in a spot that gets plenty of sun.
You’ll have probably heard about nasturtiums before – they’re widely regarded as the go-to plant for companion planting, and with good reason too. They’re known to release a potent insecticide-chemical that wards off whiteflies, squash bugs, aphids and the overwhelming majority of beetles.
It’s also a favorite of some species of bee, so you’ll be doing your bit for nature’s pollinators too! Most people plant nasturtiums around their vegetable beds, but they can also be planted in mixed borders for great results too.
Yarrow is one of our favorite insect repellents. Its natural oils are known to repel mosquitos and other, flying insects. In fact, tinctures made from yarrow are supposed to be stronger than DEET and dotting some plants in amongst your other flowers is a sure-fire way to drop the insect population overnight.
It’s actually yarrows insect-attracting effects that make us such a huge fan of Yarrow though. This delicate little plant is a favorite of ladybugs and its nectar attracts predatory wasps that’ll quickly wipe out unwanted insect populations.
Often dismissed as a ‘filler’ plant, ageratum is actually a great choice if you’re looking to keep bugs out of the garden. It secretes a chemical called coumarin, which is the primary ingredient in most mosquito repellent, and it’s particularly good at forcing flying insects out of the garden. It also produces another chemical that interferes with an endocrine release in insects and renders them sterile
Oh, and the icing on the cake? It’s toxic to grazing animals, and most herbivores will actively avoid it. The only slight downside is that it can spread like a weed, so make sure you keep it in check!
With this list of insect-repelling plants, you should be able to head out, and pest-proof your borders and beds. Companion planting can be tricky though, so if you have any questions about the advice given here – or you want to learn more about using these plants to bolster your garden’s natural insect defenses – just send us a message using the contact form on our site.