Choosing plants for Beneficial Habitat At Home

light pink flower with a fuzzy bee crawling on it
A bee gathers pollen from a cosmos flower.

Recall from this post that I’m creating habitat for beneficial arthropods (including insects, spiders, predatory mites, etc.) around my house this spring. Because more of us may be doing this while we’re staying home to keep each other safe, I’m sharing my experiences here (as well as on Twitter and Instagram). The previous post covered site selection. Today I will talk about the species I’ve chosen (and why).

What I’m planting in my yard

Sunny yard alongside a house with several freshly-dug garden beds
My side yard faces south and gets the most sun. But it’s a pretty small area and I want it to look reasonably tidy. I’m still building rapport with my neighbors.

The front and side yards get plenty of sun (because they face south and west), so I’m looking for plants that thrive in full sun. And I’ll admit that I’m interested in more than just supporting beneficial arthropods. I also want my front and side yards to look reasonably nice. (I don’t want to make enemies of my new neighbors!) And I want to grow flowers for cutting. So I am not sticking strictly to native plant species or to perennials. Some plants I picked just because I thought they looked nice. For example, I was beguiled by ‘Chim Chiminee’ Rudbeckia. The pollen and nectar produced by the native species may have been bred out of this variety. I’ll find out. I also just love ‘Persian Carpet’ zinnias.

Plants growing in a large clump with smaller flowers in combinations of yellow, orange, and red.
I grew these ‘Persian Carpet’ zinnias in my garden last year. I love the mix of colors and the abundant blooms that last well when cut.

I’ve started a lot of plants from seeds I had in my fridge (e.g., snap dragons, echinacea, bachelor’s buttons). Others I will direct-seed outside (e.g., sunflowers, zinnia, cosmos), and I may also purchase some transplants from local nurseries (many have great strategies for safe curbside pick-up!).

Several small seedlings growing in paper pots.
I’m starting some plants from seed at home. Using paper pots means that I can compost them when I’m done, and not worry about carrying pathogens over from year to year on plastic pots that I would have to wash very thoroughly after use. Once a plant pathologist, always a plant pathologist!

Choosing plants for beneficial arthropods – the basics

Which plant species to grow to support beneficial arthropods (whether it’s pollinators or natural enemies of pests, or both) is a common question. The answer is both straight-forward, and also complicated. In addition to shelter and protection from pesticides, all beneficial arthropods need something to eat. In general, plants that provide plenty of nectar and pollen help to provide this food. Many natural enemies of pests will also eat pollen or nectar (e.g., at certain life stages, or as a supplement to the pests they eat). Even if they don’t, the pollen and nectar will often attract small arthropods that natural enemies can feed on. So, the simple answer is that a plant that produces lots of pollen and nectar, will thrive in the setting where you want to plant it, and is not invasive is a good choice for supporting beneficial arthropods. Plants that are marketed as supporting pollinators are easy to find and are likely to also support natural enemies.

Bright purple flower with three petals with a yellow and black striped fly perched on it
This Ohio spiderwort (Tradescantia ohiensis) in our beneficial arthropod habitat plots is being visited by a hover fly. Hover fly larvae are excellent aphid predators!

But, of course, it’s not exactly that simple…

Choosing plants – natives, cultivars, and more

Many people ask if they should only grow native plant species, or if it’s ok to plant cultivated varieties of native species, or non-native species. (Hopefully it’s obvious that you should never plant an invasive species in your yard!) Annie White at the University of Vermont wrote a 254-page dissertation on the topic. These two sentences from her abstract summarize her findings nicely: “Our study shows that many insect pollinators prefer to forage on native species over cultivated varieties of the native species, but not always, and not exclusively. Some native cultivars may be comparable substitutions for native species in pollinator habitat restoration projects, but all cultivars should be evaluated on an individual basis.” You might also want to take a look at this article from the University of Maryland and this one from the Xerces Society. In summary, I would say it’s up to you whether you want to plant exclusively native species, or not.

According to David Smitley from Michigan State University, perennials are usually better choices for bees than annuals, but this article includes a list of annuals that are attractive to bees. Alyssum is an annual that definitely supports natural enemies, but many of the other annuals on this list may also support natural enemies.

Deep orange sunflower with a bee visiting it, starting to gather pollen
Although they are annuals, sunflowers are still very attractive to bees. Also, I like them as cut flowers.

Choosing plants – attracting specific arthropods

If you are trying to attract very specific natural enemies (e.g., parasitoid wasps, lady beetles) your plant choice can also get more complicated. Some great work has been done by researchers at Michigan State University documenting which arthropods (pollinators, natural enemies, and some pests) visited different plant species native to Michigan. They also offer a simplified summary. “Habitat Planning for Beneficial Insects” from the Xerces Society includes notes in the charts at the end about which beneficial insects are particularly attracted to the species listed. This resource from Oregon State University describes some specific plants and the arthropods they support. Finally, although this study was conducted in the United Kingdom, there might be some relevance to the Northeast U.S.

Update: During Summer 2020 (while I was doing less field work), I reviewed the literature I could find on the value of specific plants for specific natural enemies. Here is the spreadsheet I compiled.

Lists and searchable databases

In addition to the resources already listed, you may find the following helpful in selecting plants:

If you want to focus on native plants, there are many organizations committed to supporting local native plants…too many to list here, but some online searching may turn up an organization that is local for you.

My current plant list

This table lists what I either have already seeded (inside or outside), or am planning to direct seed outside when it gets a little warmer. In addition to the common, scientific, and cultivar name of each plant and whether it is a perennial or an annual in NY, I also included information about why I chose it. I only marked plants as supporting bees or natural enemies if I could find documentation of that fact in the resources above. It may be that more of the plants on this list support beneficial arthropods. If you have additional information on these plants, please let me know! In some cases (for example, zinnia) the species is reported to support beneficial arthropods, but I don’t know if the cultivars I’m growing will. In many cases, the decorative value of the plant was a big part of why I chose it. The arnica? Well, I just saw that in a seed catalog this winter and ordered some on a whim.

Common name Scientific name Cultivar Annual or Perennial in NY Bees Natural enemies Decorative
Arnica Arnica chamissonis perennial
Bachelor’s buttons Centaurea cyanus annual X X
Blanketflower Gaillardia aristata Burgundy perennial X X X
Blue vervain Verbena hastata perennial X
Calendula Calendula officinalis Remembrance Mix annual X X
Celosia Celosia argentea cristata Red Flame annual X X
Cosmos Cosmos bipnnatus Dwarf Sensation annual X X X
Echinacea Echinacea purpurea perennial X X
Marigold Tagetes erecta Senate House annual X X
Poppy Papaver somniferum Frilled White Poppy annual maybe X
Poppy Papaver sp. seed saved by a colleague annual maybe X
Pyrethrum daisy Chrysanthemum cocineum perennial X
Rudbeckia Rudbeckia hirta Chim chiminee perennial maybe X
Snap dragon Antirrhinum majus annual X X
Strawflower Xerochrysum bracteatum annual X
Sunflower Helianthus anus Mammoth Greystripe annual X probably X
Sunflower Helianthus anus Evening Sun annual X probably X
Sunflower Helianthus anus Sonja Dwarf annual X probably X
Zinnia Zinnia elegans Queen Lime with Blush annual maybe X
Zinnia Zinnia elegans Candy Cane Mix annual maybe X
Zinnia Zinnia elegans Benary’s Wine annual maybe X
Mexican zinnia Zinnia haageana Persian Carpet annual maybe X

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program. All images are hers, unless otherwise noted.

This work is supported by:

  • Crop Protection and Pest Management -Extension Implementation Program Area grant no. 2017-70006-27142/project accession no. 1014000, from the USDA National Institute of Food and Agriculture.
  • New York State Department of Agriculture and Markets
  • Towards Sustainability Foundation