Protecting pollinators

There’s good and bad news about neonicotinoid pesticides during this spring’s plant shopping season. A Vanderbilt study that exposed honey bees to low doses of neonics found that after three days, the bees were sleeping half as long as normal. That’s bad news, because sleep-deprived bees have trouble finding their way back to the hive and may starve and die. 

Neonic-exposed sleep-deprived bees can't navigate

    Bees memorize visual cues for short flights, but when they’re farther from the hive, they navigate by using their circadian clock and their position in relation to the sun. Neonics disrupt bees’ circadian rhythms and throw off this navigation process.

    We seem to be accumulating more and more evidence that these pesticides harm pollinators, but the Environmental Protection Agency still hasn’t made up its mind to ban them or restrict their use, as the European Union has done. A ruling is due this year.

    As I made my plant shopping lists, I had to decide again whether to buy from my favorite garden centers. Could I trust them not to sell neonic-treated plants? I got some good news from two sources. A nearby farm stand with a large garden shop told me that most of their seedlings are started on site, and they don’t use neonics. They’ve switched to biological controls. This opens up a good source for common annuals I buy every year, such as lobelias, marigolds, alyssum, and coleus.

Pollinator-friendly marigolds and Mexican sunflowers, neonic-free

    Jack Russell, the owner of Russell’s Garden Center in nearby Wayland, called back in response to my inquiry about whether plant offerings at Russell’s are neonic-treated. I was relieved to hear his qualified no. Jack said their vegetable plants are neonic-free. For perennials and annuals, he said, they try not to sell anything treated with neonics. 

    The problem for Russell’s and other garden centers is the number of stops plants make on their way to market. Russell’s can certify that their suppliers aren’t using the insecticides, but they can’t be sure that seedlings or seeds weren’t treated before they got to those wholesale producers. Unfortunately, neonics persist for years in plant tissues.

Before planting, I want to be sure native moss phlox doesn't carry poisonous neonics

 
    Some of the suppliers whose plants I buy at places like Russell’s have made a strong commitment not to use neonics. Proven Winners, which produces many of my annuals, has vowed not to treat their plants, although they don’t quite admit that neonics harm bees. Most of the herbs offered at garden centers that I frequent are produced organically at Gilbertie’s Herb Gardens in Connecticut, so I know they’re neonic-free.

 
    In general, edible plants are less likely to be treated than ornamentals. Apparently sellers understand that consumers want pesticide-free food, but they’re slower to grasp how concerned we are about poisoning pollinators.

It's a relief to be able to source neonic-free annuals

    The good news is that the retail market is gradually catching up with ecological gardeners’ preferences regarding neonics. I’m delighted to be able to revisit my favorite plant shopping venues. Now if the EPA issues a ban, we’ll really feel sure that our gardens are safe for pollinators.

Alyssum that's safe for pollinators

 

Pollinator-friendly container plantings

Every spring I fill 10 or 12 large containers with flowers and foliage plants for summer enjoyment. At this time of year, there’s a pause in the garden action. Foliage is looking shopworn and dull. A few flowering plants whose growth shut down during the hottest days are coming back to life, preparing for an autumn round of bloom. 

Phlox and a few zinnias are blooming in the late summer lull

Buds are swelling on the New England asters (Symphyotrichum novae-angliae), but few have opened yet. This seems like a good time to evaluate how the container plantings have turned out.

    My favorite pot this year was inspired by advice from reader Patricia McGinnis. Two years ago, Patricia pointed out that instead of neonicotinoid-treated annuals from the garden center, I could fill my pots with divisions of perennials from the garden. What a breakthrough!

    Last fall I’d potted some unneeded perennials with thoughts of passing them on to students at my spring sustainable gardening course (If you’d like to attend the fall course in my garden on Saturdays October 26 and November 2, you can register here through Newton Community Education). Some didn’t find a new home, so I used them to design a pot for a prominent position in the front yard.

Perennial divisions fill out a front yard container

    A purple-leaved heuchera, a nativar, makes a solid mass in this arrangement. Nonnatives provide contrasting foliage: a hosta with chartreuse leaves banded with blue-green and a Japanese forest grass (Hakonechloa macra) with similar yellow-gold coloring. I bought an ostrich fern (Matteuccia struthiopteris) to add some height and added white-flowered wax begonias to bloom nonstop through the season. The begonias' shiny round leaves add another texture to the composition. I knew the fern and begonias were neonic-free, because I’d gotten them at a local farm and garden center that promises untreated plants.

    My next favorite container plantings this summer feature nonnative combinations I’ve been repeating over the years. The “thriller” in these pots is Canna ‘Bengal Tiger’. 

Yellow-striped leaves make Canna 'Bengal Tiger' stand out

I store the roots in the basement through the winter, so I don’t have to worry about neonic-treated replacements. I do the same with the giant tuberous roots of elephant ears (Colcasia esculenta). 

Like cannas, elephant ears need their roots stored indoors in winter

The canna has orange blooms, but I usually cut off the flower stalks so top-heavy plants won’t tip over in a heavy wind. To fill in around the canna stems in a pot that’s located in shade, I added white-flowered impatiens. In two pots on the deck that get afternoon sun, I combined the cannas with cobalt-blue lobelia (Lobelia erinus). 

    This year I’ve had success with another conventional flower choice: a big pot full of apple-blossom pink geraniums. 

Taking a break on a geranium flower. Is it a cricket?

I’d bought three of these plants at a pesticide-free garden center two years ago. I’ve kept subsequent generations alive by taking cuttings in fall. This way I don’t have to search every spring for neonic-free geraniums.

    These are the adaptations that have allowed me to keep neonics out of my pollinator-friendly garden. I’m also happy that my peat-free potting mix is succeeding in providing sustenance for the container plantings.

Coleus thriving in potting mix made from compost and coconut fiber

A bit of progress on neonics

This week I planted a sunflower that I’d bought at Home Depot. My reason for shopping at a big box store instead of a local garden center was the progress Home Depot has made toward phasing out neonicotinoid insecticides from their plant offerings.

Sources of neonic-free plants can be hard to find

    Thanks to a campaign by Friends of the Earth and others, Home Depot yielded to pressure and promised that plants they sold would be neonic-free by 2019. Neonics are systemic pesticides that are used to promote growth and keep plants on retail benches looking fresh and unchewed. The problem is that they also kill or disable bees and other pollinators.

Neonics can kill bees that visit treated plants

     Once a seed or plant has been treated, neonics persist in plant tissues for years and can even be transmitted to nearby plants through soil and water contamination. In 2014, Friends of the Earth found neonics in more than half of bee-attracting commercial nursery plants bought at a broad sample of garden centers and big box stores in the United States and Canada. 

    As they worked on purging neonics from their supply chain, Home Depot took the interim step of labeling neonic-treated plants they sold. 

Home Depot's spin on neonic labeling

They got some negative responses to this practice, because it raised awareness of the danger. Meanwhile, other sellers continued selling treated plants without the warning. This year Home Depot says that 98 percent of the plants they sell are untreated. They attribute the remaining 2 percent to state regulations requiring neonic treatment of certain plants. 

    Meanwhile, I’ve failed totally at growing sunflowers from seed in my garden. When I plant seeds, something bites off the seedlings as they emerge. I imagine this is a squirrel who likes the taste of sunflower sprouts. I’ve tried starting the sunflowers indoors and transplanting young seedlings to the garden. These young plants too have been irresistible to hungry wildlife. That’s why I decided to buy a husky sunflower whose stems are already tough enough to withstand squirrels’ teeth. 

    I bought what was offered: ‘Sunfinity,’ a hybrid that grows to only 3 feet and produces multiple 3- to 4-inch flowers through the season. This plant won’t offer seeds for the birds. It produces nectar for beneficial insects, but it’s sterile, with no pollen. 

Sunflower 'Sunfinity'

This is not the sunflower of my dreams. I’d envisioned something taller with a few dinner-plate-sized blooms packed with seeds. Planting so late, though, I’ve got a chance of seeing the flowers bloom.

    When I encountered the plant, it was showing some flowers. I took care of that by planting it in the vegetable bed, where something quickly bit off the young blooms. 

Stripped

 Undeterred, the plant put out some more buds that are now opening. I imagine that this back and forth will continue into the fall.

Trying again

    I wish Home Depot offered some unhybridized sunflowers, straight Helianthus annuus. Those would do more for pollinators and birds in the garden. But I’m glad to know that my Sunfinity is neonic-free. There’s no point in a pollinator garden that kills pollinators.

First do no harm

Hard choices

A garden club member recently asked me how I would deal with an infestation of gypsy moth caterpillars on a mugo pine (Pinus mugo). Last summer her tree was crawling with them. 

Nonnative gypsy moth caterpillars can cause massive defoliation

Would I use pesticides in this situation? Fortunately gypsy moth populations wax and wane on a predictable cycle. In wet years, like the one we just had, a fungus that kills the caterpillars surges. We can expect minimal gypsy moth damage this summer, so her tree should get a break. Her question raises a larger issue, though. When is it right to use pesticides?

    I was recently disillusioned to learn that the Arnold Arboretum is using a neonicotinoid pesticide to control massively destructive hemlock woolly adelgids in its vast collection of eastern hemlocks (Tsuga canadensis).

White cottony masses on this hemlock are adelgid egg cases

Following the lead of Great Smoky Mountains National Park managers, they’re taking a two-pronged approach to this nonnative pest. They’re spraying the trees with horticultural oil, which smothers the insects, and they’re drenching the soil around the trees with imidacloprid, which attacks their nervous system.

Gray trees in this view of the Smokies are hemlocks killed by adelgids-photo NPS

     In the Smokies, this treatment is reducing adelgid damage and even resulting in regrowth of some hemlock foliage (When it’s not applied to soil, the pesticide is injected into the tree’s bark). Hemlocks are foundational species in the park. Park managers decided that losing them all was unacceptable.

Drenching soil with pesticide-photo NPS

    I sympathize with their dilemma and the Arboretum’s. We resolve to limit our use of pesticides or ban them outright. Then a threat to a plant we can’t bear to lose makes us break our promise to ourselves. As an Arboretum staffer writes, “. . . we are an essential resource for a large urban population that for over 150 years has enjoyed . . . a majestic hemlock-dominated forest.”

Hemlock forest

    The problem, of course, is that all pesticides cause collateral damage. I stopped spraying hemlocks in my yard with horticultural oil for hemlock woolly adelgid two years ago when I realized that even spraying in early spring was killing some insect bystanders that I didn’t want to lose. 

Spraying for adelgids could kill bumblebees and other early foragers-photo Ivtorov

The USDA acknowledges that in the Smokies, imidacloprid affects insects in tree canopies and in the soil at their feet.

    It was human activity that brought the adelgid from Japan to North America. It has no natural predators here. Some human response seems to be needed before all our hemlocks succumb, but what should it be? Applying a pollinator-killing neonicotinoid seems like an unhappy choice. 

     One hopeful development in the Southeast: introduction of natural predators from Japan that eat only adelgids. 

Biocontrol beetle eating adelgids

Tiny beetles in the genus Laricobius have been released in the forest and succeeded in decreasing the adelgid presence without affecting native insects. The hope is that a new balance will develop between these predators and their adelgid prey. Foresters in some areas have been able to stop the chemical treatments. 

     The beetles will never kill every last adelgid, but they may allow hemlocks to survive. Was it worth using pesticides before the beetles became available? I guess so.

Insect-friendly in 2019

Judging by last year, seed catalogs will start arriving this month. I’m beginning to think about how to keep neonicotinoid insecticides out of next year’s garden.

Seed catalogs should be arriving soon

    Evidence is piling up that “neonics,” widely used in agriculture, are ubiquitous in the environment and the food supply. This class of chemicals was developed in the 1980s to replace earlier pesticides that were more toxic to humans. In the years since, they’ve played a part in a massive insect die-off. Neonics persist in plant tissues and kill or disable non-target insects, traveling by wind and water to affect untreated wild and cultivated areas.

Neonics kill and disable bees

    The problem goes beyond pollination. Insects also play a crucial role at the base of the food web and do essential work recycling waste through decomposition. Without insects, Earth wouldn’t support much human life (My thanks to reader Patricia McGinnis, who forwarded a revealing New York Times Magazine piece on this subject).

    In the midst of this gloom, I got some good news recently when I phoned a local garden center, Allandale Farm, to ask about their practices. I knew that the farm uses only organic controls on their site. The grower I spoke with reassured me that they also don’t buy any plants that have been treated with neonics. They’ve been able to find smaller nurseries that don't use these pesticides, she said. I was delighted to hear it. 

 

May plant shopping is a fun tradition

My lingering doubts about buying perennials at the farm were dispelled. Because garden centers source some of their stock from other growers, I’d feared that the farm might be selling neonic-treated plants from elsewhere. Now that I know their plants are neonic-free, I can enjoy a shopping spree in May. It’s great to hear that there are small wholesalers out there producing neonic-free plants. I hope they prosper!

    I feel good about shopping at local garden centers like Allandale Farm. At the other end of the scale of plant retailing, Home Depot promised in 2015 that they would phase out neonic-treated plants by the end of 2018. In the interim, they required their suppliers to attach a warning label to plants exposed to the chemicals. This is all progress, but I don’t see any statement on Home Depot’s web site announcing that the neonic phase-out is complete. Let’s hope that will be forthcoming next spring.

    Meanwhile, I’ve developed a short list of seed catalogs that offer organic seed. Conventional growers use treated seed to introduce neonics into a plant’s life cycle; organic growers don’t. Unfortunately it’s much easier to find pesticide-free seed for starting vegetables than for flowers.

Organic basil seeds weren't hard to find last year

     There’s still not enough consumer demand for organically grown ornamental plants. As one grower said to me, “You’re not going to eat them, so what’s the point?” The point is that we want to protect the soil and the creatures that live around us!

Here’s my list so far of catalogs that offer some organic alternatives: 

*Natural Gardening Company 
Johnny’s Selected Seeds
Renee’s Garden
*Adaptive Seeds
Botanical Interests
*Seeds of Change
Burpee
                        *organics only

Fooling some of the people all of the time

My email has brought me some interesting news relating to neonicotinoid insecticides. I received a message from the Friends of Newton Cemetery announcing that they’re creating a pollinator garden with a grant from Bayer. The cemetery is a beautiful park, generously open to the public. I wondered whether its horticultural staff knew that their garden to provide forage for pollinators was to be funded by one of the world’s top manufacturers and sellers of pollinator-killing neonics.

Newton Cemetery October 2017

    Bayer makes the best-selling neonic, imidacloprid, sold as Admire, Advantage, Confidor, Gaucho, Merit, Hachikusan, Kohinor, Premise, Prothor, and Winner. 

Merit

They also sell two other successful neonics, clothianidin and thiacloprid. Despite mounting scientific evidence, Bayer has consistently denied that neonics harm pollinators, including bees. They blame other factors, such as varroa mites, for the bee die-off. Their Bee Care Program and the entity that made the grant to Newton Cemetery, FeedABee, seem to be part of a campaign to combat negative publicity for Bayer’s insecticide products. Viewed in this light, the gift to the cemetery seems less community spirited.

How dumb do they think we are?

    But a pollinator garden is a good thing. I don’t see why the cemetery can’t accept Bayer’s money for an environmentally positive project. They just shouldn’t use it to buy plants treated with Bayer’s products, or other neonics. The insecticides persist for years in treated plants. Bees that contact them die or suffer neurological damage. 

Neonics can kill whole colonies or do more subtle harm

    I wrote back to the Friends of Newton Cemetery to ask whether they’ve found a source of reliably neonic-free annuals and perennials. In my experience, this has been a difficult quest, but a necessary one. Who wants a pollinator garden that kills pollinators?

I grew these marigolds from organic seed, so I know they won't kill bees

    Meanwhile, there’s some good news on the horizon about neonics. The Massachusetts legislature is considering a bill to ban the direct sale of the insecticides to consumers in our state. I was delighted to hear from my state senator, Cynthia Creem, that she cosponsored the bill, H4041, An Act to protect Massachusetts pollinators. Since the EPA hasn’t banned neonics, it’s up to the states to take action.

    Even if neonics aren’t sold directly to consumers, though, they’ll still affect insects in our gardens as long as garden centers and big box stores sell treated plants. Plant production is a global business. Wholesale nurseries source seeds all over the world. They buy tiny annual seedlings from rooting stations around the US and tissue culture products imported from as far afield as South Africa, Holland, Turkey, and Poland (tissue culture converts tiny pieces of plant tissue into large numbers of genetically identical plantlets). Giant plantations in Costa Rica and Ecuador send cuttings of perennials for US wholesalers to root and grow to saleable size.

The annuals we buy are international travelers

    As long as plants can be treated with neonics at any of these stops on their way to market, gardeners still risk exposing pollinators to the dangers of these chemicals. Home Depot has promised that its plants will be free of neonics by the end of 2018. It’s a start.

Neonics' notoriety

Evidence keeps piling up against widespread use of neonicotinoid insecticides. Reacting to a critical review by its scientific branch, the European Union recently banned the use of the chemicals except in closed greenhouses.

Neonics harm bumblebees

Some of the bad news:
•    Populations not just of honeybees, but also bumblebees and solitary bees, important pollinators, are declining in many countries where neonics are widely used. If they don’t die, exposed bees have fewer queens and may be neurologically impaired, losing their navigational ability.
•    Neonics are found in water, soil, and wildflowers near fields of treated crops. Insects can contact the pesticides without visiting the crop plants.
•    Three out of four honey samples from around the world and 86 percent in North America contained neonicotinoids.
•    Neonics have been found in food, and claims that they’re harmless to vertebrates are losing conviction; for example, exposed sparrows lost weight and got lost during migration.

This swallowtail caterpillar's food could be contaminated

As with climate change, the science is complicated, and the pesticide industry is still saying there isn’t enough evidence that neonics are causing the bee die-off. An alarm sounded when a German study showed a 75 percent decrease in flying insects over a 25-year period, but this wasn’t attributed to neonics alone. Analysts opined that habitat loss and widespread use of pesticides were both major determinants. In the US, it’s thought that neonics may weaken insects’ immune systems, making them susceptible to epidemics caused by fungi and mites.

Honeybee on a black-eyed Susan

    What’s to be done? New systemic pesticides are already being introduced, but that hardly seems like a solution. Farmers in the UK objected to the European Union’s ban, saying the pests they needed chemicals for are still around. I hope farmers will transition toward methods that minimize pesticides and preserve insect habitat.

    On my tiny scale, I’m still trying to keep neonics out of my garden but recognize that I’m not fully succeeding. I bought only untreated seed this year—treated seed is the way neonics are often introduced into the commercial growing process, and they persist in tissues as the plants grow. My favorite garden center promises that they don’t use pesticides, but does that mean their plants are neonic free throughout the life cycle? In today’s nursery trade, seedlings change hands repeatedly.

I can't be certain this 5-year-old caryopteris is neonic-free

    I’ve fallen back on reproducing my own plants by spreading seed or making cuttings or divisions.  I got a new generation of purple coneflowers (Echinacea purpurea) by cutting off the flower heads of some organically grown plants in fall and scattering them in an area where I wanted more plants. Two years later, many new coneflowers are blooming.

Purple coneflowers are popular with bees

    To make my new bed, I dug out and transplanted wedges or whole offspring from existing perennials: variegated iris (Iris pallida), columbines (Aquilegia spp), dwarf goat’s beard (Aruncus aethusifolium), and goldenrod (Solidago spp). I’m growing some new bearberry (Arctostaphylos uva-ursi) from cuttings.

This hoverfly is another hardworking pollinator at risk

    Making new stock from my yard’s plants would exclude pesticides if I’m right that the plants started out untreated, but if not, I’m just perpetuating contamination.
   

Paradigm shift needed

One characteristic of the post-World War II era was cheery optimism about the potential for solving problems with synthetic chemicals. Perhaps the best example was DDT, which was going to rid the world of insect-borne disease. Look how well that turned out.

Spraying DDT over Oregon forest, 1955

    In the fifties and sixties, we all tended to trust safety and effectiveness claims for household and garden chemicals. Synthetic fertilizer was going to make soil stewardship irrelevant by spreading unlimited quantities of the basic plant nutrients, nitrogen, phosphorus and potassium. We learned that doing this destroys soil fertility while causing dead lakes and rivers as fertilizer runs off fields and lawns into nearby waterways.

Fertilizer runoff causing algae overgrowth and eutrophication

    There was 2,4-D, invented as a defoliant during the war and brought home as Scotts Weed and Feed to eliminate broad-leaved weeds from American lawns. 

     Imagine what would have happened if Scotts had brought home Agent Orange from the Vietnam War—by then, public attitudes toward war materials had shifted significantly. Since the 1940s, 2,4-D has taken us down a path toward increasing insistence on monocultural lawns, with all the water and chemical inputs necessary to maintain them.

Grass doesn't grow this way naturally

    The 1970s brought Roundup (glyphosate), marketed by Monsanto as a benign product to spare us the trouble of bending down to pull weeds. 

Roundup is ubiquitious

By the 1980s, genetically engineered “Roundup-ready” crops resistant to the herbicide enabled spraying this product on agricultural fields. Farmers took up the practice on a massive scale. As a result, we’re all eating Roundup, which a United Nations agency has declared a probable human carcinogen, a hormone disruptor, and a contributor to antibiotic resistance.

    Neonicotinoid pesticides, my garden nemesis, are the next in this series of chemicals first thought to be harmless. From the 1960s to the 1990s, the most commonly used pesticides were organophosphates, which had high toxicity for humans, other mammals, and birds. Neonics are safer for the people applying them, and since the nineties they have dominated the market, used for treating both seeds and growing plants. 

     Now we know that neonics are very persistent in plant tissues and toxic to many insects, including honeybees and other pollinators. 

Neonics poison pollinators

I recently learned that some insects have already developed resistance to neonics. That’s the predictable result of widespread use of any pesticide, analogous to development of antibiotic resistance in treated bacteria.

    Maybe we can stop thinking about living systems in such simplistic ways. Instead of charging in with blunt instruments like herbicides and pesticides, we need to think about what keeps natural systems in balance. Diverse populations and healthy growing conditions help plants to weather the onslaught of pests and diseases. Every organism has its place in a natural community.

Biodiversity protects plant health

    Insect populations are dropping worldwide. We need insects if we’re going to continue living on earth. Times have changed since the fifties. We’ve stopped watching TV Westerns. Let’s also stop thinking of plants and insects as good guys versus bad guys.