Another reason to keep garden waste at home

A new book that came in the mail, The Pollinator Victory Garden by Kim Eierman, made me glad that I'd started a brush pile this fall. Until recently, I couldn’t picture a suitable spot for this amenity in my third-of-an-acre suburban lot.

    The ecological reason to cultivate a brush pile is to provide wildlife habitat. Kim Eierman’s book focuses on insects, so she recommends brush piles as shelter for bees. She points out that 30 percent of North America’s 4,000 native bees are cavity nesters. They need safe small spaces where they’re sheltered from the rain. Some find cavities that birds or other insects have made in dead trees, stumps or fallen logs.

Carpenter bees are cavity nesters-photo Anita Gould

    Other than wood chip mulch, there’s a shortage of dead wood on the ground in our yard, due to my previous habit of cleaning up at soil level. I now realize that’s unnecessary and eliminates potential habitat for creatures I want in the garden. I’m allowing dead tree limbs to lie on the ground in inconspicuous spots, but it’ll be a while before they soften and rot.

This downed tree in a local conservation area offers shelter for native insects

    The brush pile I’ve started intends to serve a dual purpose: containing our over-enthusiastic puppy and offering shelter for wildlife. Eager to play together, our Lola and Ruby, the dog next door, discovered spots where they could dig under the wooden fence between their yards. 

"Who, me?"

They applied themselves with energy. I went to work reinforcing our perimeter with wire fencing held down with bricks, paving stones, and any big rocks I could find. 

    There was a vulnerable space between two wire compost bins and the new chain link fence that joins the wooden fence line. I blocked off this corner with more wire fencing. In addition to foiling a homegrown prison break, the narrow, enclosed space now houses my new brush pile. As I build up the pile, I plan to add bundles of twigs tied with twine to keep insect nests dry.

Starting the brush pile with pine branches that came down in a heavy wind

    Cavity-nesting bees also find spaces inside plant stems. I’m already accommodating them by letting stalks stand through the winter. We’ve got elderberry, raspberry, and hydrangea bushes, so I’m glad to hear that their pithy stems make particularly good nesting spots.

Spongy stems of oak leaf hydrangea can be excavated by bees to make nests

    I love the idea of an insect hotel. That’s a human-made collection of promising nesting material, such as bunches of hollow stalks tightly packed together, clumps of dry leaves, cut lengths of bamboo stakes, ceramic blocks with small cavities built in, and tree branches or chunks of lumber with holes drilled for convenient insect access. 

This is an insect hotel in Germany. Cool, right?

The thing about this approach, though, is that the cavities need periodic cleaning. I’m not sure I can be counted on to clean an insect hotel on a regular schedule. For now, I’m letting nature do the work.

    After reading the first chapter of Kim’s book, I can already tell it’s going to up my game. While I wait to put Kim’s advice into practice next spring, I’ll be throwing fallen branches on the brush pile instead of filling yard waste bags.

 

Brainy insects

Scrolling through a web page about pollination syndromes—ways flowers are designed to get themselves pollinated--published by Vanderbilt University, I was intrigued to see some insects referred to as unintelligent. Magnolia flowers are so primitive and simple, the authors said, that they can be pollinated by “relatively unintelligent insects like beetles” crawling around, bumping into anthers and getting dusted with pollen. Does this mean that some insects are considered intelligent?

Beetles pollinating magnolia flower, dumb but effective-photo Beatriz Moisset

    Yes, it turns out that they are. It seems that the investigation of insect intelligence has been hindered by our tendency to look for human-like cognitive abilities, which insects may not need. As scientists shrug off this bias, they’ve found that social insects tend to be the smartest. It seems that finding food and shelter are less cognitively challenging than dealing with members of one’s social group. I can relate. That’s why beetles aren’t so smart. They’re solitary.

    Fleas and ticks are at the bottom of the intelligence scale. All they need to do is find their host for a blood meal. 

Deer tick: all brawn, no brains

They don’t need other information from their environment, and they don’t depend on social interactions. Somehow, the idea that ticks are dumb isn’t surprising.

    The smartest insects include bees, wasps, ants, termites, and cockroaches. Termites are prime exemplars of swarm intelligence, acting in concert to build and engineer large, complex, constantly evolving structures. As such, they’re attracting attention from designers of robots. 

Termite hill-photo Adityamadhav83

Paper wasps have been shown to recognize each other’s faces, and researchers hypothesize this is necessary for surviving in the wasps’ complex social hierarchy! Ants don’t wander around randomly, as was once thought. They have advanced navigational abilities and can leave a chemical trail for their fellows. 

Ants tending citrus mealybugs-photo Katja Schulz

Cockroaches can learn how to respond to a novel situation and then judge whether the same response is likely to work when a new situation arises. 

    Bees seem to be the smartest of all. They start life ignorant of how to find food. A young bee figures out how to “operate” each type of flower to get the nectar she’s looking for. She uses observation, learned knowledge, and memory to solve problems. Bees can count up to four. They can even recognize and distinguish between human faces.

Honey bee on Camassia flower-photo victorberthelsdorf

    Then there’s the waggle dance, evidence of bees’ advanced communication ability. A bee recalls where she found food and tells her mates the location with a dance on a vertical surface inside the hive. Moving straight up means traveling in the direction of the sun, straight down means away from the sun, and angles away from the vertical line show the direction to fly to find the nectar source. If it’s a really great source, she’ll dance many times—the equivalent of shouting. The waggle dance means bees can share information without leading their sisters to the food source or otherwise attracting attention from competitors.

Bee waggle dance-figure designed by J. Tautz and M. Kleinhenz, Beegroup Würzburg

    Knowing that insects can think motivates me to give them their space in the garden. Maybe they’re observing me to assess my intelligence.

Spare those weeds

Pulling out weeds always seems like a virtue, and letting them grow a sign of slovenliness. But it turns out that a few weedy patches promote biodiversity in the yard. 

A neighbor has let these weeds take over a stretch of curb strip

When we removed large hemlocks last year to avoid spraying them for hemlock woolly adelgid, we were left with two sunny clearings. I planted native shrubs and small trees, but it’ll be a few years before they grow big enough to fill the space. Meanwhile, lots of weeds have stepped forward to fill the open space.

A stand of what I think is hawkweed taking over some newly sunny ground

    With the idea that this could be a good, I’ve been looking up our weeds in Wild Urban Plants of the Northeast, Peter Del Tredici’s guide to “spontaneous urban vegetation.” Many are listed as “disturbance-adapted colonizer of bare ground,” true to their behavior in my yard.

    One of their useful functions is to provide food and habitat for beneficial insects, the ones that prey on leaf-eaters. Although these insects are predators in at least one life stage, they often need nectar and pollen in another. That’s one way that weeds such as lamb’s quarters and chickweed can be a plus.

Lamb's quarters wilting in this week's heat

Their flowers provide extra forage and fill in during the lean times when our preferred flowers aren’t blooming. Weeds may also attract prey insects that the beneficials need to eat or parasitize. 

    Here are some of the weeds that have popped up where the hemlocks grew:

Pokeweed (Phytolacca americana): This is a North American native that, although toxic to mammals, has fruits that birds love. At least 30 bird species use pokeberries as a major food source. 

Pokeweed grows quickly into a substantial presence

Warblers and other migratory birds eat them on their flights south. The berries help mockingbirds, cardinals, cedar waxwings, and others to get through the Northeastern winter. Pokeweed is larval food for several moth and butterfly species, including the giant leopard moth. Bees feed on its pollen.

Giant leopard moth-photo NPS Phillip Brown

Yellow woodsorrel (Oxalis stricta): Also a native, this low perennial shows up all over my garden. At summer camp we called it sour grass and chewed on the leaves when we were thirsty on a hike. 

Recognize this yellow woodsorrel? It's all over the place.

The plant’s tissues are high in oxalic acid, so it’s better to sample the leaves in moderation. It too provides seeds for birds, pollen for native insects, and leaves for butterfly and moth caterpillars.

Devil’s beggarticks (Bidens frondosa): This native annual gets the prize for its many colorful names: sticktight, devil's bootjack, pitchfork weed, Spanish needles. You can see it hasn’t made a lot of friends among gardeners, but it provides pollen for bees and, interestingly, food for muskrats when it grows near water.

Devil's beggarticks has pretty flowers; its bad rep comes from the burrs that follow.

    These weeds are easy for me to pull out, especially because they’re growing where I previously put down a layer of wood chip mulch. Under the wood chips, the soil stays soft. I’ll remove some weeds that are shading my squash and melon plants (a story for another day), but now I know to leave some for their contribution to the garden’s ecology.

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.
   

Choosing the right plants for the right pollinators

As I think about planting this spring, flowers for pollinators are a high priority. But beyond choosing pollinator plants from lists for Northeast gardeners, how can I know which flowers will deliver the best value for these insects? By turning to Jessica Walliser, one of my garden heroines. Jessica recently posted a great article about types of pollinators and what they need.

Bumblebees like a spacious landing pad

    Come to think of it, all pollinators aren’t the same, so it’s not surprising that they need different things from flowers. I was eager to see how I was doing with the types of insects Jessica described.

    Bumblebees are big and heavy enough to pop open flowers to get at enclosed nectaries. That means they benefit from lupines, snapdragons, and many pea-type flowers, including my white redbud (Cercis canadensis f. alba). 

Redbuds' flower shape show they're in the pea family, Fabaceae

I do have some native lupines, and I enjoy snapdragons. The challenge will be to find some this year that aren’t treated with neonicotinoids. Jessica points out that spraying pesticides will harm pollinators, making your whole planting effort moot. Bumblebees also have long tongues that enable them to extract nectar from flowers with deep throats, such as my phlox, bee balm, and salvias.

Phlox 'David'

    Thousands of species of native bees (North America has 4,000 in all) are tiny insects that need plants with lots of small flowers. They like daisy flowers such as black-eyed Susans (Rudbeckia species). 

Black-eyed Susans work for smaller bees

I’ve got lots of these popping up all over, thanks to their generous self-seeding. A daisy’s central disc is actually packed with many small flowers, each offering pollen for these little bees. Sunflowers and coreopsis provide the same architecture. 

A sunflower's central disc contains many tiny flowers

Small bees also like the tiny clusters of flowers sported by plants such as my goldenrods (Solidago species).

Goldenrod goes for quantity over size

    Native bees don’t build hives. They’re mostly solitary, often raising their young in holes in the ground or in hollow stems, which they may also shelter in during the winter. Last fall I followed Jessica’s advice and left flower stems standing. 

Don't just take it from me. New York's High Line leaves coneflowers standing too.

They’re looking kind of messy now, but I hope to see more pollinators this spring. I learned from this post that I could cut them to 15 inches high if I don’t want them flopping over. Some of the plants I grow that have hollow stems are purple coneflowers (Echinacea purpurea), raspberries, and ornamental grasses. 

    Pollinators need flowers blooming throughout the growing season. Witch hazel is offering some pollen now. Other early bloomers that will help in my yard include bugleweed (Ajuga species), catmint (Nepeta species), and shadbush (Amelanchier canadensis). At the end of the season, asters, goldenrods and sedums help keep the buffet open.

A monarch found this New England aster

    Jessica confirms something I learned recently. Double flowers don’t do anything for pollinators. That’s because in breeding for doubleness, the pollen-carrying stamens are converted into extra petals. Even if the insects could fight their way through to the flower’s center, there’s no nectar there for them to get. So when you’re confronted with dozens of coneflower cultivars, skip the double ones if you’re shopping to please pollinators.

These double coneflowers don't offer nectar or pollen

Buyer bee-ware

It’s seed ordering time again. I’m receiving fat catalogs every week bursting with alluring color photos of flowers and vegetables to grow from seed. Last year I wrote about trying to adapt my seed and plant purchases to avoid neonicotinoids, bee-killing pesticides ubiquitous in the nursery trade. What’s the point of a pollinator garden that kills pollinators?

When you plant for pollinators, you don't want toxic flowers

    To refresh your memory, in 2013, Friends of the Earth (FOE) conducted a landmark study, publicized in their report Gardeners Beware. Sampling plants from garden centers and big box stores across the country, they found widespread presence of neonicotinoids (called neonics for short) in the plants offered to consumers. 

    FOE’s Bee Action campaign continues. With other environmental organizations as allies, they’ve succeeded in mobilizing consumers to oppose use of these pesticides. 

Shoppers prefer their flowers without insecticides

There’s good information regarding neonics on the Friends of the Earth website, including a handout on how to recognize and avoid the neonics sold in the US: acetamiprid, clothianidin, dinotefuran, imidacloprid, and thiamethoxam. 

     You can watch for these names and avoid pesticide sprays that contain them, such as Ortho Flower, Fruit and Vegetable Insecticide and Bayer Advanced Complete Insect Killer. I’ve never been desperate enough to resort to these broad-spectrum insecticides in my garden, but I understand how gardeners can panic and reach for a spray bottle.

Before spraying chewed leaves, give beneficial insects time to solve the problem by eating leaf-eaters

    Neonics are systemic insecticides that insects take in when they eat or touch treated plant tissues, as when bees collect pollen from flowers of treated plants. 

Neonic-treated pollen can poison bees

They may die immediately, become disoriented, or pass on the poison to others in the hive. Once treated, plant tissues continue to hold the toxins almost indefinitely. 

    Neonics are widely used to maximize yield and keep plant foliage looking clean and unchewed as plants pass from growers to distributors to garden centers. We don’t have to spray neonics ourselves to poison pollinators in our yards; our plant purchases will be toxic to insects unless we purposely avoid neonic-treated plants.

Garden center seedlings may be contaminated with neonics

    The Friends of the Earth campaign has convinced some major retailers to stop using neonics or label treated plants: here’s a link to their list. BJ’s Wholesale Club promised that their plants would be neonic-free or labeled by the end of 2017. Home Depot committed to completing its neonic phase-out by 2018. Lowe’s pledged to work on it. True Value says their plants will be neonic-free by spring 2018.

    Unfortunately Massachusetts is not a leader in this effort. National campaigns like FOE’s have more leverage with big nationally visible chains than with local businesses, apparently. I’ve had luck shopping at Allandale Farm in Chestnut Hill, which doesn’t use conventional pesticides and commits to sustainable practices. 

    As I plan my seed purchases for 2018, I’ll let you know where I find organic seeds and pesticide-free seeds. 

They don't make seed catalogs like they used to

I believe this is a temporary problem; eventually the nursery business will bow to consumer pressure and provide us with reliably neonic-free seeds and plants. Will they convert to pollinator-friendly methods? That depends on whether we keep up the pressure.

At the Climate March, April 2017

Neonics reprised

Beekeepers are spreading the word: neonicotinoid pesticides are bad news for honeybees. A Boston Globe story last week about bee-friendly yards spotlighted the problem. While choosing native plants is a help, beekeepers interviewed emphasized that you undo your good work if you apply toxic pesticides on your property—or if someone nearby sprays these chemicals.

Black-eyed Susans help pollinators--but not if they're treated with toxic neonics

    Friends of Earth and its supporters are asking EPA administrator Scott Pruitt to ban one of the neonics, imidacloprid. The National Pesticide Information Center at Oregon State University reports there are 400 products sold in the US containing this pesticide in various forms: liquids, granules, dusts, and water-soluble powders. A quick search turned up brand names such as Temprid, Maxforce, and Bayer Insect Control. 

    So far the EPA has declined to ban agricultural use of imidacloprid. Plants sold in garden centers may be even more of a problem. 

Tempting, but garden center plants could be toxic for pollinators

They can be treated with the pesticide at 120 times the concentration used on farms. Because the neonics dissolve in water, they migrate into all plant tissues and can contaminate surrounding soil. They’re slow to degrade and can affect your garden for years to come.

    As garden center customers, we have reason to feel betrayed. We’re encouraged—urged—to buy pollinator-friendly plants. Wouldn’t it be reasonable to expect that those plants won’t kill pollinators?

    Beekeepers are of course most concerned about honeybee die-off. In late June, a beekeeper in Rehoboth, Massachusetts lost more than 60,000 bees. Knowledgeable observers say this loss has the hallmarks of pesticide poisoning. Bee scouts go out each morning to find sources of pollen and nectar. They return to the hive to share their information. The Rehoboth bees seem to have followed their scouts to a nearby food source contaminated with pesticide.

A contaminated food source can kill a whole hive--photo by Shawn Caza

     This is the kind of effect neonicotinoid spraying can have. A homeowner could have used a pesticide product according to label instructions, or worse, could have applied more than instructed or sprayed at a windy time when the spray would be carried to surrounding areas. The result: bee genocide.

    We hear most about honeybees, but there are 400 native bee species on the job too pollinating our food crops as well as other plants. 

Bumblebees are important pollinators too

Moths and butterflies also do this work. Neonics threaten all these insect pollinators. 

    Since becoming aware of the neonic problem this year, I’ve been working hard to avoid bringing home any neonic-treated plants. Plant purchases from previous years may already be spreading toxicity on my land. I searched for untreated seeds, or at least seeds sourced from European countries that don’t allow neonic treatment. I found places to shop where sellers guarantee their seedlings are pesticide-free, if not fully organic. But I had to avoid my favorite garden center, because they’re still buying neonic-treated plants.

Stokesia from a pesticide-free garden center

    Big retailers such as BJ’s Wholesale Club and Home Depot have already pledged not to sell neonic-treated plants. It’s high time that local garden centers did the same.