While there’s been a lot of focus on promoting pollinators in the news lately, let’s not forget about supporting all the other beneficial insects that reside in our yards and gardens. There are thousands of species of predatory and parasitic beneficial insects who help us control many common garden pests by consuming them or using them to house and feed their developing young. If you want to encourage these pest-munching bugs, then you’d do well to include plants for beneficial insects in your garden plans.
Beneficial Insects in the Garden
There are about a million identified insect species on the planet, and less than 1% of them are classified as agricultural pests. That means the vast majority of insects you encounter in your garden are either benign or beneficial. In other words, they’re just hanging out in your garden, doing their jobs.
The insects we most want to encourage in our landscapes, of course, are those that help us in some way. And, in my humble opinion, no other group of insects does that better than the predators and parasitoids. In a healthy garden – one filled with a diversity of plants and devoid of pesticide use – these beneficial insects are capable of consuming tens of thousands of pests every single day. If left to do their work, beneficial insects, such as ladybugs, lacewings, predatory stinkbugs, soldier beetles, tachinid flies, parasitic wasps, and many others, make a significant dent in pest populations.
Related post: Rudbeckias – Powerhouse plants
Attracting Beneficial Insects
In order to boost populations of beneficial insects, you don’t need to buy them and import them into the garden (more on this potentially dangerous practice here). Instead, you should focus on promoting and supporting the beneficial insects already living there by providing them with food and habitat.
Most species of beneficial predatory and parasitic insects require the carbohydrates in nectar, in addition to the protein provided by their prey. For example, though ladybugs are voracious predators in the garden, they also require nectar for reproduction, and parasitoids like parasitic wasps and tachinid flies consume only nectar as adults; it’s their larvae who are predaceous.
What this means is that, without plenty of appropriate nectar sources, your garden will not be able to support a hearty population of pest-munching beneficial insects, and you may find yourself battling more pest issues than you’d like.
Related post: Build a beetle bank or bump
What are the Best Plants for Beneficial Insects?
Most beneficial insects do not have the specialized mouthparts needed for accessing nectar from deep or tubular flowers. Instead, they need to feed from tiny flowers with shallow, exposed nectaries. They simply can’t access nectar from the same plants with big flowers or hidden nectaries that many larger species of bees prefer.
This means that to support beneficial insects, you need to tailor your plant selections to suit their needs. There are many studies in existence, with many more in-progress, that examine which flowers are the most appropriate nectar sources for predatory and parasitic beneficial insects. It’s exciting for a bug-nerd like me to see so much research taking place on this topic and the results are fascinating.
Below you’ll find a list of some of the best plants for beneficial insects. In addition to being excellent nectar sources for beneficial insects, most of these plants are also lovely garden specimens. Be sure to include as many of these plants as possible in your garden to attract, encourage, and support a broad diversity of beneficial insects.
- Achillea millefolium – yarrow
- Ammi majus – laceflower
- Anethum graveolens – dill
- Angelica species – angelica
- Baccharis species – baccharis
- Boltonia asteroides – boltonia
- Coreopsis species – tickseed
- Cosmos bipinnatus – cosmos
- Eriogonum species – native buckwheat
- Eupatorium perfoliatum – common boneset
- Helianthus annuus – sunflower
- Leucanthemum x superbum – shasta daisy
- Labularia maritima – sweet alyssum
- Phacelia tanacetifolia – lacy phacelia
- Pycnanthemum species – mountain mint
- Ratibida pinnata – praire coneflower
- Rudbeckia species – black-eyed Susans
- Solidago species – goldenrod
- Spirea alba – meadowsweet
- Symphyotrichum species – hardy aster
- Veronicastrum virginicum – Culver’s root
- Zizia aurea – golden Alexanders
- Zizia aptera – heartleaf Alexanders
In addition to planting these plants, always allow your garden to stand through the winter months so beneficial insects have a place to overwinter. Check out this post for more reasons why you shouldn’t clean up your garden in the fall.
How do you support beneficial insects in your garden?
Thank you! This, including the post on not doing intensive “fall cleanup” may be the most universally useful blog post I’ve ever read. Perhaps one more thing to emphasize might be the importance of sticking to as many native plants as possible.
Jessica Walliser says
Thanks, Mike! That’s high praise! 🙂 The bugs thank you and we do too!
MB Whitcomb says
Agreed on picking natives. Introduced angelica species here in Cape Breton have hybridized with our native A. sylvestris and created a superweed that is overwhelming native plant populations. See the You Tube Lectures by Doug Tallamy for the hard (and eye-opening) research on the importance of natives. Note: I am not an “all natives” person, but the problem of invasive species is very bad in some areas and some groups are dismissively recommending planting of plants that may benefit people in the short term but can cause great harm. I have seen this idea in permaculture, and it distresses me because permaculture is encouraging people to garden who have never gardened before and who may cause a “green explosion” before they understand what the ramifications are. Written by a person who would rather be gardening than fighting plants.
Leila Oertel says
Thank you. I agree. When I heard and further a blog on a popular radio gardening site recommend loosestrife, I wrote to him with your same comment. His reply distressed me. He essentially said that it isn’t all that bad and I was being overly cautious. Well, that ended my time with his blog.
MB Whitcomb says
LOL, the only reason that purple loosestrife is not worse is because no less than four predator insects were introduced to eat it. Often these attempts backfire in some way, but they do seem to be helping control this terrible wetland killing plant.