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In the midst of the worst winter—ever—it’s hard to think about flowers, I know. But this time of year, I normally order a few plants for spring delivery from catalogs and I’m having to spend a lot more time on that than usual because I want to make sure that the flowers I’m ordering aren’t going to kill the bees that visit my gardens. By now you’ve probably heard that many of the pollinator-friendly plants and flowers that we’ve been filling our gardens with over the last few years may actually be harming, and even killing, bees.
Photo Bob Peterson
The culprit, many scientists and researchers believe, are neonicotinoid pesticides. Widely used in lawn fertilizers and on crops and nursery plants, neonicotinoids (commonly called neonics) came on the market in the 1990s and are chemically related to nicotine.
Marketed as safer for humans than other pesticides, neonics are now thought to be at least in part responsible for declining bee populations all over the world. Let me explain why. Like all systemic pesticides, neonics are absorbed by plants after being applied to the leaves, seeds or even soil. When bees and other pollinators feed on the leaves, flowers and pollen of plants treated with neonics, they ingest a “dose” of the insecticide.
Though the makers of these pesticides contend that the amount ingested by insects, including bees, is not enough to kill them, entomologists who study bees believe otherwise. Neonicotinoids are neuroactive, meaning they block connections in the brain. Over the last several years, studies have shown that even after ingesting small amounts of neonics, bees can become confused to the point of being unable to identify food sources. Some even forget how to find their way back to the hive. Over time, without food from the hive’s forages, colonies starve and collapse.
Vera Krischik, an entomologist at the University of Minnesota, has been studying the effects of insecticide on bees for several years. She has found that large doses of neonics can kill bees, sometimes moments after they feed on a treated plant. Where are they getting these large doses of neonicotinoid pesticides? Possibly, my garden, I hate to say; or maybe yours, or your neighbor’s. That’s because it is legal to treat ornamental plants with much higher levels of neonicotinoids than are acceptable for use on agricultural crops like corn and soybeans. And because pre-treatment of nursery plants is so common these days, it’s very likely that most of us have brought home some of these plants in the last few years without realizing the harm they could be doing.
Photo by orangeaurochs
What Can Gardeners Do?
So what can we do now? Well, that’s going to take a bit of work on our part. Concern over whether neonicotinoids are harming bees is not new, and Krischik is just one of many researchers across the country. and the world, who have spoken out about the problem. As a result, some European countries have restricted or banned some neonicotinoids.
But, as is usually the case, our U.S. Environmental Protection Agency has opted to take a wait-and-see approach and has decided to look at the insecticide as part of a standard registration review. That could take years—years that bees don’t have. Though it is good news that the Minnesota Department of Agriculture and the Department of Natural Resources seem to have taken the issue more seriously since the start of the year.
For now, fellow gardeners, help must come from us, so we need to do all we can to keep neonics out of our gardens. That means growing some of our plants ourselves using seeds collected from plants we know to be untreated or purchased from retailers who don’t sell pre-treated seeds such as Seed Savers Exchange, Baker Creek Heirloom Seeds and Renee’s Garden Seeds.
Shopping for plants will be trickier and in some cases, more expensive. Home Depot and Lowes may offer lower prices on ornamental plants, but so far Home Depot has indicated that they plan to continue selling plants treated with neonics until they can work with suppliers to find an alternative insecticide. I don’t know about Lowes, but I imagine that selling far fewer plants to gardeners who won’t buy anything treated with neonics might speed talks up a bit.
Honey bee swarm photo by kevincole
Before buying plants from any seller, ask them whether they use neonics or buy plants treated with them. To help, I made some calls for this article to see how various growers and garden centers are dealing with this issue. Glacial Ridge Growers in Glenwood, Minnesota, sells native plants free of neonics. Bachman’s, Gertens and Menards didn’t return calls before my deadline, so you’ll need to ask them yourselves. Mother Earth Gardens says they don’t sell any flowering, edible or fruiting plants treated with neonics, though they do carry a few non-flowering trees that have been treated with the pesticides.
Scott Endres, co-owner of Minneapolis’ Tangletown Gardens, told me that though he can’t guarantee that every single plant they sell is neonic-free, almost every single plant is neonic-free because they grow the majority of them themselves and know exactly how they are produced. When they do buy something they want to carry but don’t grow, he says they buy from reputable growers they trust, so consumers can feel confident buying plants from them. Scott also said that he thinks it’s “awesome” that more and more gardeners are insisting on plants grown “with organic principles that support a sustainable product and the earth.” He believes that people’s awareness is already creating demand that is pushing companies to think more closely about their practices. I couldn’t agree more.
Hi,
Would you know if caffeine could have the same effect on bees? We get our elm tree treated against bugs every three years or so, and the treatment is based on a caffeine formula.
Hi,
Interesting question. I did a quick search and found that Science magazine, among other publications, have published reports that bees actually get a helpful memory boost from caffeine. So it doesn’t seem like you need to be concerned about the treatment you’re doing for your elms. – Meleah
Are we already too late? I have scarcely a bee in my large garden . and am trying to just plant bee-attracting plants from now on.
Prairie Moon Nursery, also in MN, as well as Niche Gardens in NC, and Streambank Gardens in DE are also neonic-free. The majority of the plants sold by Lazy S;s Farms Nursery in VA are also clean. I grew all my own annuals this year to solve the problem of not bringing neonics into my garden. I’ve also decided to only plant perennials in the winter after their bloom time so that even if they have been given a systemic, by the time they bloom the following year, the chemicals will no longer be active. There are also several nurseries in my area (outside DC) that are carrying organic/pesticide free annuals/herbs/veggies. As horrifying as this issue it, there does seem to be a current of change flowing against it. Thanks for continuing to educate.
Are perennials that were probably grown with neonics that I ordered spring 2013 and are growing now, going to be safe for pollinators this season? Kathleen
Hi Kathleen,
It’s hard to say whether those plants will be safe. I’ve interviewed a couple of researchers working on this issue and asked that same question. If plants were treated with a neonic foliar spray rather than given a soil drench of the pesticide, levels of neonics will drop more quickly. How quickly is hard to predict because it depends on how much was used and growers and nurseries apply what they opt to apply as there is no standard. Research that is available shows that neonics can persist in woody plants for up to five years, less in herbaceous plants like perennials. So it’s likely that neonics are still persistent in plants you bought last year, but they may not be lethal or even terribly harmful at this point. It’s hard to know. Most gardeners are in this spot this year. For what it’s worth, I’m not going to rip out my plants and throw them away. I’m just going to try to avoid adding any more plants that contain neonics to my garden.
Thank you, Meleah, for your quick response. It’s a dilemma, for sure. Once I read about the poisonous pollen, I’ve read all I could about it, with no info about how long it persists. I welcomed your reply and will make my decisions as informed as possible this season and all the following ones. With gratitude, Kathleen Broughten (A member of the Mendota Heights Garden Club, I heard your talk last year.)