Insect-friendly gardens

A sphecid wasp on mint. This wasp is a grasshopper hunter. (Photo by Margot Monson)

For all the gardeners and flowering plant lovers who want to create an environment that attracts beneficial insects to your yards and gardens, consider choosing your plants with extra care this spring. This includes the potted plants and baskets of colorful annuals you may choose for gifts.

For a good start to attracting a healthy balance of beneficial insects to your garden, probably the most important factor is selecting many different plants, including those native to Minnesota, which will attract a diverse population of insects. You may attract a few herbivores but also the pollinators who eat them, such as predacious beetles, ants, flies, parasitic wasps and bees, the larvae of the lovely delicate lacewings, and don’t forget predatory spiders, which are all beneficial.

When choosing native plants, it’s best to avoid cultivars and hybrids. When plants are bred for deeper colors or larger blooms than those that occur naturally, the quality of pollen and nectar is diminished. Beware of the term nativars, which refers to natives that have been genetically modified. They will not be the same as pure natives in quality of resources available for our insects.

In addition to natives, be sure to look for bee-friendly plants, including vegetables and herbs, that will offer good nectar and pollen resources. The quality of the food sources available for insects is an important reason to plant a diversity of plants, because, just like humans, insects need a balanced diet to be healthy.

Although they may be forced to range longer distances, honeybees typically fly about two miles in search of pollen and nectar. When they are surrounded by genetically modified (GM) monocultures in farm fields in the country, they often find only one food source because the landscape is nearly devoid of wildflowers. They also take in harmful chemicals when attracted to self-pollinating GM agricultural crops like corn.

In our cities, if you look closely, most flowers are exotics, hybrids and cultivars, so our pollinators are becoming increasingly nutritionally deficient.

Beware of pretreated plants and seeds

After this long cold winter, many of us are eager to get out in the sun and into the garden to plant seeds for herbs and vegetables, or even to choose a pot of colorful flowers that will tolerate the temperature fluctuations in the early spring. Here is where we need to be cautious about our choices, because far too many seeds and plants are pretreated with systemic pesticides.

A sphecid wasp on butterfly weed. (Photo by Margot Monson)

Often called the neonicotinoids or “neonics,” these chemicals are marketed under several names and sold by many companies. Systemic pesticides permeate the entire plant, including the nectar and pollen, and may remain toxic for long periods.

In the case of perennials that die back in the fall, these chemicals may remain in the roots and soil for years, becoming a part of the entire plant again as it emerges the following spring.

Pesticides in the form of contact sprays may be shorter lasting, but if in contact with the flowers, will still affect the pollinating insects.

Another less well-known practice is the purchase of cuttings from outside the United States. A surprising number of nurseries are importing these cuttings from which they propagate their plants. The cuttings arrive pretreated to pass inspection when going through U.S. Customs.

Our laws do not require pesticide labeling, so ask the nursery about the systemic neonics when purchasing plants.

Save the dandelions for the bees

Dandelions are considered the first source of good nutrition for our native bumblebees, which are even more efficient pollinators than honeybees. The queens begin emerging to search for new nest sites as soon as the temperatures are warm enough for them to fly.

We have become so conditioned to think of these bright yellow flowers as undesirable weeds, but the bumblebees need them. Please do not use herbicides on such important early resources, which are so nutritious for our largest and most gentle of bees.

Pollinators need diverse plants

Research is revealing that honeybees and bumblebees are bringing many different chemicals back to their hives, and together with a lack of enough diverse plant resources for adequate nutrition, pesticides further weaken them, making them more susceptible to diseases. Our pollinators are really struggling to find diverse and untreated resources in our urban areas, and due to the increasing transformation taking place in rural landscapes from agricultural crops, country pollinators are at a great disadvantage, as well.

As an entomologist and beekeeper, I do not use synthetic preparations in our gardens, and with a diverse assemblage of plants, I have few pests. Occasionally there are large populations of a particular pest, like the Japanese beetles of two years ago, which were definitely an annoying problem, but the numbers of predatory native bees, wasps, lacewings, beetles, flies, ants and spiders that I regularly see in our gardens generally take care of anything that does show up.

Honeybees and monarchs are attracting a lot of attention now because bees are responsible for pollinating at least a third of our food crops, especially fruits, vegetables, nuts and dairy products, and we can easily recognize and identify monarchs as our most amazing migratory butterflies. Since we can estimate their populations and count them, so to speak, their rapidly declining numbers are being documented, but there are thousands of species of native insect pollinators also at risk. Whatever impacts these honeybees and monarchs will affect all our pollinators.

How can gardeners hoping to create healthy habitats in their own yards and gardens distinguish these treated plants among the huge displays we will soon see in most large grocery and hardware stores, garden centers, nurseries, farmers markets and small businesses? Ask each supplier about where they bought or how they grew the plants on display. Let them know that you do not want to introduce anything pretreated into your garden or display a pot or basket of treated annuals.

Letting our growers know what we believe to be environmentally healthy gardening practices and voting with our dollars may begin to influence their decisions about their methods. It is not an exaggeration to say we desperately need all native insects to produce sustainable populations in order to have healthy environments in which to grow our gardens and for all our wild creatures to survive, including the insectivorous birds, reptiles, amphibians, mammals, and so, us.

Resources for a native plant garden

Many native plants grow well in gardens, but your soil, moisture and sun conditions will determine your success. Creating a native habitat is a process. It took more than three years before my perennials became established, filled in and provided successive blooms throughout the growing season. Even after 30 years with the same gardening space, I still am learning, discovering new pollinating insect visitors, and trying new plants each year. With climate change we are seeing different insect species surviving here and plants are reacting to the changes as well.

You can find lists of natives at these websites:

• www.minnesotawildflowers.info
• www.dnr.state.mn.us/gardens/nativeplants
• www.xerces.org/pollinator-conservation

Native Plant Expo

Meet many native growers and discover new native plants at the St. Paul Audubon Society’s Native Plant Expo and Market on Saturday, June 7, 9 a.m.-3 p.m., in the Rainbow Foods Community Pavilion, 1201 Larpenteur Ave., Roseville.

SAPSA plant sale

This year St. Anthony Park Elementary School’s spring plant sale, a fundraiser for St. Anthony Park School Association (SAPSA), will be on Thursday and Friday, May 8 and 9, at the school, and will include some plants sourced from Glacial Ridge Growers, a company committed to organic and sustainable practices in its fields and greenhouses.

Learn more

A workshop on combatting the sale of pretreated plants will be held on Saturday, April 5, 9 a.m.-noon at the John B. Davis Hall, Macalester College, 1600 Grand Ave. The workshop, sponsored by the St. Paul Audubon Society, will be free and open to the public. Happy spring planting, and may your gardens be busy buzzing this summer.

Sources for Natives and Untreated Plants

Egg Plant Urban Farm Supply, 1771 Selby Ave, St. Paul, 651-645-0818: eggplantsupply.com. Egg Plant carries seeds from Seed Savers in Decorah, Iowa; Renee’s Garden in California, and Botanical Interests in Colorado, all of which sell conventional and organic seeds. The company also sells fruit trees, shrubs, berries from Bailey’s Nurseries  (some treated),  and plants from Rush Creek Growers. Ask questions about specific plants.

Glacial Ridge Growers, Glenwood, Minn., 320-634-0136  or 866-518-1671: glacialridgegrowers.com. Glacial Ridge sales wholesale to nurseries, food co-ops, garden centers, fundraisers and farmer’s markets. They use no insecticides, herbicides, growth retardants or GM seeds. The use predatory insects for pest control.

Gardens of Eagan, Northfield, Minn.,  507-645-2544: info@gardensofeagan.com. For cut flowers, contact jennifer@humblepiefarm.com. Gardens of Eagan has an outstanding reputation and is certified organic. The company grows all its seeds. The seeds and plants are not treated. They supply farmer’s markets and food co-ops.

Hampden Park Co-op, Raymond and Hampden avenues, St. Anthony Park,  651-646-6686: hampdenparkcoop.com. Hampden park sells plants from Glacial Ridge Growers— no pretreatments, no pesticides. Glacial Ridge uses predatory insects for pest control.

Landscape Alternatives, 25316 St. Croix Trail, Shafer, Minn., 651-257-4460: landscapealternatives.com. Landscape Alternatives is an excellent source for natives and the owner knows his natives.

Mother Earth Gardens, 3738 42nd Ave. S., Minneapolis,  612-724-2296, amd 2318 N.E. Lowry Ave., Minneapolis, 612-789-0796: motherearthgarden.com. Plants are grown by Rush Creek Growers. Ask questions about specific plants.

Prairie Moon, 32115 Prairie Lane, Winona, Minn.,  866-417-8156: info@prairiemoon.com. Many seeds are collected from wild natives; others are from seed companies. Prairie Moon propagates some plants; others are contracted from trusted local independent growers. No neonicotinoid systemic pesticides. They do use some pyrethroids, synthetic pesticides that are approved for organic use but may be toxic to pollinators. Ask questions about specific plants.

Prairie Restoration, Scandia, Minn., 800-837-5986, prairieresto.com: Prairie Restoration has a large selection of plants for all Minnesota habitats  and excellent advice on natives. Plants are grown only from their seeds

Tangletown Gardens, 5353 Nicollet Ave So., Minneapolis, 612-822-4769: www.tangletowngardens.com. Plants are grown at a greenhouse in Plato, Minn., from Seed Savers Seeds and are propagated from their own plants. They use predatory insects to control pests.

The Vagary, Randolph, MN 507-263-5369: www.thevagary.com. Excellent website for perennials, natives and growing conditions. Nancy knows natives.

Sources for Untreated Seeds

Baker’s Creek Heirloom Seed Company, 2278 Baker Creek Road, Mansfield, MO 65704, 417-924-8917:  bakercreekheirloomseed.com. All seeds are non-GMO, nonhybrid, nonpatented, nontreated and include many heirlooms.

Fedco Seeds, P.O. Box 520, Waterville, ME 04903, 207-426-9900: fedcoseeds.com. Untreated vegetable, herb and flower seeds.

High Mowing Organic Seeds, 76 Quarry Road, Wolcott, VT 05685, 802-472-6174: highmowingseedscom. One hundred percent organic and non-GMO seeds.

ION Exchange Native Wildflower Seed & Plant Nursery, Iowa, 563-419-0837: ionxchange.com. No pretreatments, ION grows all their own seeds and plants.

Johnny’s Seeds, 877-564-6697, P.O. Box 299 Waterville, ME 04903: johnnysseeds.com or customerservice@johnnyseeds.com. Many certified organic untreated seeds and heirlooms and some conventional.

Don’t miss the Native Plant Expo

Landscape Revival: Native Plant Expo & Market: Saturday, June 7, 9 a.m.-3 p.m., 1201 Larpenteur Ave. W,, corner of Larpenteur and Fernwood. The market will include native growers only. You can meet many growers in one place.

Additional references

Boyd. R. 2013. “It’s Time for a Neonicotinoid Time Out.” Scientific American. (blogs.scientificamerican.com/plugged-in/2013/03/14/its-time-for-a-neonicotinoid-time-out/.)

Brown. T., S. Kegley, and L. Archer. 2013. Gardeners Beware: Bee-Toxic Pesticides Found in “Bee-Friendly” Plants Sold at Garden Centers Nationwide. Friends of the Earth. www.FoE.org www.BeeAction.org

DeVore, B. 2009. A Sticky Situation for Pollinators. MN ConservationVolunteer. (www.dnr.state.mn.us/volunteer/julaug09/pollinators.html)

Whitehorn, P.R., S. O’Connor, F.L. Wackers, and D. Goulson. 2012. “Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production.” Science 336: 351-352

Xerces. 2013. Scientists Call for an End to Cosmetic Insecticide Use After the Largest Bumble Bee Poisoning on Record. The Xerces Society for Invertebrate Conservation, June 2013.

Beyond Pesticides. Daily News Blog. New Study Exposes Range of Harm from Neonicotinoid Pesticides. Sources from David Goulson, Ph.D., University of Sussex, Journal of Applied Ecology

Margot Monson is an entomologist and beekeeper and is passionate about insect conservation.