—by Margot Monson
For all the gardeners and lovers of flowering plants who wish to create an environment that attracts beneficial insects to your yards and gardens, choose your plants with extra care this spring. This includes plants you may choose for gifts in the form of pots and baskets with colorful annuals.
Selecting native plants
For a good start to attracting a healthy balance of beneficial insects to your garden, choose a diversity of plants native to Minnesota. This will attract a diverse population of herbivorous insects and the predators who eat them, such as beetles, ants, flies, and parasitic wasps (most of which are also pollinators), the delicate predatory lacewings, and don’t forget the beneficial predatory spiders.
When choosing natives, look for those that are not cultivars, hybrids, or genetically modified "nativars," because when plants are bred for deeper colors or larger blooms than those that occur naturally, the quality of pollen and nectar is diminished.
Many native plants are easy to grow, but your particular soil, moisture, and sun conditions, (and the color of your thumb, though that can change) will determine your success, so creating a native habitat is a process and journey. It took at least three years before my perennials became established, filled in, and provided successive blooms throughout the growing season, and even after 30 years with the same gardening space, I still am learning, discovering new insect visitors, and trying new plants each year.
If natives are not your only preference, then be sure to look for bee-friendly flowers, vegetables, and herbs that will offer good nectar and pollen resources.
Diversity of food sources
Insects, like humans, need a balanced diet to be healthy. The more diversity in your garden, the better for the insects.
One reason honey bees are in trouble is a lack of plant diversity in rural areas. In order to be most efficient and successful in foraging, honey bees typically fly only about two miles in search of pollen and nectar, but when surrounded by genetically modified (GM) monocultures, they typically find only one food source because the landscape is very nearly devoid of wild flower sources.
Even in our cities, most flowers are exotics, hybrids, and cultivars, so our pollinators are becoming increasingly nutritionally deficient.
Research is revealing that honey bees are bringing many different chemicals back to their hives. These chemicals, together with a lack of diverse plant resources that provide adequate nutrition, weaken the bees, making them more susceptible to disease.
After this long cold winter I am anxious to get out in the sun and into my garden. This often includes a trip to the greenhouse to buy seedlings and pots of flowers. Here is where we need to be very cautious, because far too many seeds and plants are pretreated with systemic pesticides, often called neonicotinoids or “neonics,” but also marketed under several other names and sold by many different companies.
Systemic pesticides permeate the entire plant, including the nectar and pollen, and depending on which chemicals and in what combinations, 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 affect the pollinating insects.
A surprising number of nurseries import cuttings from which they propagate their plants; these cuttings arrive pretreated in order to pass inspection when going through U.S. customs.
Bee friendly, bee aware
Our pollinators are really struggling to find diverse and untreated resources in our cities, and, due to the increasing transformation by agriculture in rural landscapes, country pollinators are at a great disadvantage, as well.
As an entomologist and beekeeper, I do not use any synthetic preparations in our gardens, and with a diverse assemblage of plants, I have few pests. Yes, occasionally there are large populations of a particular pest species, such as the Japanese beetles of two years ago which were definitely a problem, but the predatory native bees, wasps, lacewings, beetles, flies, ants, and spiders that I regularly see in our gardens take care of anything that does show up.
Nor do I remove dandelions from my yard, because they are an essential early spring source of nutrition for our native bumblebees.
Honey bees and Monarch butterflies are attracting a lot of attention now because bees are responsible for pollinating at least one-third of our food crops, and we can easily recognize Monarchs as our most amazing migratory butterflies. Since we can estimate their populations, their rapidly declining numbers are documented. However, whatever impacts these insects will affect all our pollinators, and there are thousands of species of native insect pollinators at risk as well.
Finding safe garden plants
As gardeners and lovers of healthy ecosystems, how do we distinguish which plants and seeds to choose among the huge displays we see in most large grocery and hardware stores, garden centers, nurseries, and farmers' markets?
Because our laws do not require pesticide labeling, you will have to ask. Before you buy, find the manager or grower and ask if they are using seeds pretreated with systemic pesticides, if they pretreat their plants, and if any of their plants are grown from imported cuttings. Some companies sell both treated and untreated seeds and plants.
If they do not know what you mean by systemics, try using different names. If they will not disclose, then take your business elsewhere.
Over the past months, I have been interviewing growers in many local nurseries and garden centers as to their growing methods, and have put together a list of those I feel have answered my questions candidly. [Editor's Note: This list is available in the co-op entryway and on our website. It is not exhaustive; as awareness grows, so does the number of plant growers seeking to avoid systemic pesticides.]
Even for those on the list, as a way of helping them get the message that we are absolutely serious about not buying seeds and plants that have been pretreated, I encourage you to ask about where they bought or how they grew their plants, making them realize that you do not want to introduce anything pretreated into your garden, nor so much as to display a basket of treated annuals.
Their fate is ours
With climate change we are seeing different insects surviving here, and plants are reacting to the changes as well. We truly and quite desperately need all our native insects to produce sustainable populations in order for us to have healthy environments in which to grow our gardens and for all our wild creatures to survive, including the insectivorous birds, reptiles, amphibians, and mammals, and so, us.
[Margot Monson is an entomologist and beekeeper, and is passionate about insect conservation.]
For information on Minnesota natives:
4. One of the best experiences I’ve had meeting native growers and discovering new plants is attending the Native Plant Expo & Market. It will be held on June 7th on Larpenteur Avenue in Roseville. I guarantee you will learn something new and meet growers passionate about Minnesota wildflowers. http://www.saintpaulaudubon.org/events/ 2014/06/landscape-revival
Additional references: articles in peer-reviewed journals
1. Beyond Pesticides Daily News Blog. “New Study Exposes Range of Harm from Neonicotinoid Pesticides,” June 2013. Sourced from David Goulson, PhD, University of Sussex, Journal of Applied Ecology. http://www.beyondpesticides.org/dailynewsblog/?p=10858
2. Boyd, Robynne. “It’s Time for a Neonicotinoid Time Out,” Scientific American, March 2013. http://blogs.scientificamerican.com/plugged-in/2013/03/14/its-time-for-a...
3. Brown, Timothy; Susan Kegley and Lisa Archer. “Gardeners Beware: Bee-Toxic Pesticides Found in ‘Bee-Friendly’ Plants Sold at Garden Centers Nationwide,” Friends of the Earth, 2013. http://libcloud.s3.amazonaws.com/93/88/f/3354/Gardeners-Beware-Report-11...
4. DeVore, Brian. “A Sticky Situation for Pollinators,” Minnesota Conservation Volunteer, 2009. http://www.dnr.state.mn.us/volunteer/julaug09/pollinators.html
5. Whitehorn, Penelope R.; Stephanie O’Connor, Felix L. Wackers, and Dave Goulson. “Neonicotinoid Pesticide Reduces Bumble Bee Colony Growth and Queen Production,” Science 336: 351-352, 2012. http://www.sciencemag.org/content/ 336/6079/351.short
6. Xerces Press Release. “Scientists Call for an End to Cosmetic Insecticide Use After the Largest Bumble Bee Poisoning on Record.” The Xerces Society for Invertebrate Conservation, 2013. http://www.xerces.org/2013/06/27/scientists-call-for-an-end-to-cosmetic-...