Insectaries: Grow Flowers to Attract Beneficial Insects

Reader Contribution by Pam Dawling
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Insectary circle including borage. Photo by Bridget Aleshire

We plant selected flowers among our vegetables to attract pollinators and other beneficial insects into our garden. Farmscaping is the name for this practice on a big scale: see the ATTRA publication Farmscaping to Enhance Biological Control – CT065. The download costs 99 cents unless you are a subscriber, or if the cost is beyond your means. Oregon State Extension has a 40-page, Year 2000 version online.

After studying the literature, I made a plan and chose some flowers to deal with several garden pests and the need for pollinators. I haven’t run a trial to see whether our flowers do attract more beneficial insects than we had previously, but we do enjoy seeing the flowers. Diversity of species generally helps the ecosystem. Organic pest control improves your crop yields without harming the environment.

Spring

In spring, we plant sweet alyssum with spring cabbage and broccoli to attract insects that eat aphids. We transplant one alyssum per eight broccoli or cabbage plants down the middle of the bed, between the two rows of brassicas.

We sow the alyssum in our greenhouse in early March, on the same date as we sow replacement cabbage and broccoli. We transplant in mid-April when we replace any cabbage and broccoli casualties, 2 or 3 weeks after originally transplanting the brassicas. This works very well. We do explain carefully to our helpers not to pull them out when weeding, or smother them with mulch when we top up the hay mulch.

We also grow some repellent flowers (nasturtiums, French marigolds) and some trap crop flowers (cleome for harlequin bugs) but that’s a whole other topic.

Small, flat ,open flowers, like alyssum, borage, buckwheat, cosmos, dill, sunflowers and yarrow can attract useful insects like aphid parasites, braconid wasps, damsel bugs, lacewings, ladybugs, rove beetles, spined soldier beetles and syrphid flies. Sunflower heads are a collection of small disc flowers surrounded by ray flowers. You can simply plant out a mixture of these and watch what happens.

Or if you have a particular pest, read the ATTRA publication and make a specific plan. Ladybugs are good general helpers because their larvae eat the eggs of many different pest bugs.

Cosmos in an insectary circle. Photo by Pam Dawling

Cindy Conner pointed out a way to get early insectary flowers (if your climate is suitable) – leave your parsley or celery to overwinter. If it survives it will regrow, flower and set seed, with no extra effort on your part. Another way to have earlier flowers is to use buckwheat as a cover crop once the spring frosts are over.

At the end of April, we sow several plug flats of different flowers to plant out in Insectary. Circles at the ends of our raised beds. We include borage, calendula, cosmos, dill, sunflowers, tithonia (Mexican sunflowers) and zinnias in that sowing, to plant out in mid-late May, after the big push to transplant all our tender food crops. We used to sow earlier, but we were too busy to get them transplanted at the right time, so it’s better for us to hold off and sow later.

For suitable places to transplant our insectary circles we choose beds where the crop will be growing until the frost date. This includes chard, eggplant, leeks, okra and tomatoes.  Our focus is on food crops and we are always so busy that we have developed a method that saves time and reduces the chances of bad things happening.

As mentioned already, we get a lot of help in our garden from visitors, so we need to make sure the flowers are obvious to prevent over-enthusiastic weeding. We take old plastic buckets and cut hoops from them. (Yay! A use for cracked buckets!) We set the hoops in the soil and plant the flowers very close together inside the hoops. This flags them as something important. I plant about seven plants in each bucket hoop. It works just fine to have the flowers be just 2 to 3 inches apart.

Insectary flowers in a bucket circle.Photo by Pam Dawling

The ideal day for transplanting insectary flowers is one when rain is expected at night, as otherwise it’s a fussy little job to visit all the circles with a watering can every day. I load up a wheelbarrow, with flats leaning out the sides like wings. The hoops go on the wheelbarrow handles, and the empty watering can does, too.

I work my way along the main paths, locating suitable beds. I set the hoop on the ground and dig around outside it, putting the soil into the hoop and “sawing” the hoop down into the ground. Then I choose a selection from the flats, usually a mix of tall and short plants, transplant, water and move on. I hope to find a suitable spot every 25 feet or so.

If it doesn’t rain, I hand-water daily until each circle has had a good soaking from night-time sprinklers or rain, and it is clear the plants aren’t wilting.

Summer

All summer, whenever we sow another row of beans, we drop a sunflower seed in the furrow every 10 feet. Picking beans takes a long time and we like to have landmarks to indicate where different people started picking. The only thing worse than spending a long time picking beans is spending longer picking the same section twice!

Years ago, our seed order arrived with some split packets. Beans, sweet corn and sunflowers were mixed. We thought we had sorted them out, but accidentally got sunflowers in our bean rows. We liked the results so much that we now plant them deliberately. It also means we can point to the sunflowers in the distance and say “the beans to pick are there, where the sunflowers are.”

Sunflower in an insectary planting. Photo by Pam Dawling

Pam Dawlingworks in the vegetable gardens at Twin Oaks Community in central Virginia. She often presents workshops at MOTHER EARTH NEWS FAIRs. Pam also writes for Growing for Market magazine. Find Pam’s book,Sustainable Market Farming: Intensive Vegetable Production on a Few Acres, read her blog onher website, and connect with heron Facebook. Read all Pam’s MOTHER EARTH NEWS postshere.


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