Inconvenient clover

Speaking this week to the Wellfleet Gardeners, a wonderful group of serious gardeners on Cape Cod, reminded me of one of my favorite stories about how commercial influences form our ideas about the plants around us. Wellfleet readers, I apologize for repeating what you just heard. Tune in next week when I should be able to describe the beginning of the sheet composting experiment.

     After World War II, Americans embraced what a team of environmental scientists at Yale has termed the Industrial Lawn, defined as closely mowed, continuously green, and ideally free of weeds and pests. The Industrial Lawn requires regular inputs of water, fertilizer, pesticides, and herbicides. Energy costs are high, not just for mowing but also for synthesizing and transporting the chemicals used.

Industrial Lawn: turf grass only

     Why did we Americans embrace this Industrial Lawn, and why right after World War II? One reason was the development of an herbicide, 2,4-D, for use by the military (If this name sounds familiar, it might be because of Agent Orange, which contained both 2,4-D and 2,4,5-T, another phenoxy herbicide). During the war, chemists in England and the US raced to develop an herbicide that could wipe out German potato crops and Japanese rice, to starve out the enemy.

Spraying herbicide over Vietnam

     To their disappointment, potato and rice plants turned out to be resistant to 2,4-D. It did kill broadleaf plants in turf, though, without killing the grass. The Scotts company realized this could be a goldmine. In 1947, Scotts started selling 2,4-D in their Weed and Feed combination—herbicide plus fertilizer. Scotts had just one problem. Their new weedkiller killed clover.

     Before the war, grass seed mixes included clover seed. White or Dutch clover originated in southeastern Europe and Asia minor. It’s spread all over the world because it works so well for pastures—and lawns. I like to use clover to fill in bare patches in my lawn. Rabbits love it, and I think it’s keeping them from wiping out my perennials.

Rabbits like clover-photo ibm4381

     Clover is a legume that fixes nitrogen in the soil, in effect making lawn fertilizer. It stays green all summer; it’s easy to grow, drought tolerant, and pest free. It aerates the soil. It stays low. Dog urine doesn’t cause it to discolor; and it attracts bees and beneficial wasps that control leaf-eating insects. It sounds like an asset for any lawn, right? Before the war, that’s how it was marketed.

To me, clover looks good in a lawn

     But because of 2,4-D, Scotts changed their marketing approach. They told consumers that clover was a weed. That idea persists up to the present time; lawn care contractors still cringe at the sight of clover in the lawn.

Making killing clover a selling point

     Although we like to think that advertising doesn’t affect us, this kind of messaging has an impact. Don’t be fooled. I’m trying to grow less lawn and convert the space to more environmentally friendly uses. No matter how much lawn you like to maintain, though, don’t let anyone convince you that clover shouldn’t be part of it.

Picky eaters

Something I learned from entomologist Doug Tallamy’s book Bringing Nature Home is that most insects specialize. Ninety percent of herbivorous insects depend for food and shelter on a few plants they coevolved with. This insight is directing me toward different plant choices.

    I used to think that leaf-eating insects ate any leaves they could get. Tallamy explains that, on the contrary, over the millennia insects have survived by tailoring their behavior and physiology to be able to sense and locate a few plant species. 

Not just any leaf will do for food

They’ve synchronized their life cycles with the plants’. They’ve developed ways to get around the plants’ defenses. As they’ve invested in these food sources, they’ve become less able to live off others. That’s why most need plants from their local region and can’t eat plants from other parts of the world.

North American native insects can't eat plants that originated in Asia

    This year I’ve expanded my collection of milkweeds for monarch butterflies, the poster children of insect specialization. Monarch caterpillars have evolved to be able to eat milkweed leaves, which contain defensive chemicals called cardenolides that make the caterpillars and adult butterflies poisonous for other animals. 

A monarch on showy milkweed (Asclepias speciosa)

When eggs laid on milkweeds hatch, the caterpillars have the food they need to grow and metamorphose into another generation of beautiful adult monarchs.

    Monarchs are now under great stress. They need to fly from their winter home in Mexico to summer habitat in the US. 

Wintering in Mexico-photo Steve Bridger

Here they find less and less milkweed because of herbicides such as Roundup (glyphosate) that are widely used in industrial agriculture. Organic farmers make a point of leaving weed strips around their fields for the sake of pollinators, including butterflies. Until that becomes universal practice, home gardeners are encouraged to grow some milkweed for the monarchs.

    I started with swamp milkweed (Asclepias incarnata), which turned out to be quite easy to grow. Swamp milkweed’s dusty pink flowers are clearly an insect magnet. Not only the monarchs benefit.

Swamp milkweed attracts lots of pollinators

    This year I tried butterfly weed (Asclepias tuberosa) again. I’d planted this species twice before, only to see it dwindle without flowering. With a sunnier spot and plenty of rain this spring and summer, it didn’t flower, but it seemed to take hold. I’m optimistic about seeing some of the orange flowers next summer.

Butterfly weed, not as easy as I'd hoped.

    I also started seeds of common milkweed (Asclepias syriacus) and planted a couple of seedlings. This could turn out to be a mistake, because the plant is reputed to be quite a spreader. I like the seed pods and the seeds with their parachutes of white fleece, though, and I’m hoping to see some monarch caterpillars on the leaves.

Common milkweed seed pods opening in fall

    As an experiment, I laid a half-open common milkweed pod that I found in the neighborhood on the ground in an open area near some new shrubs. Maybe the wind will pick up some seeds and sow them as it would in the wild.

    I spotted just one monarch butterfly in the yard this summer. I hope she or he will send friends.

Front yards that time forgot

I live in a suburb with a firm code for front yard landscaping. The norm is evergreen foundation plantings—yews, hemlocks, rhododendrons, azaleas—with a well-tended lawn flowing toward the street, and possibly a privet hedge along the sidewalk.

    From the point of view of sustainable gardening, this traditional approach poses a lot of problems. Most of those evergreen shrubs are species imported from Asia that won’t provide native insects with food they need. 

    The lawn is a monocultural desert, especially if it’s fertilized and treated with pesticides and broadleaf herbicides to keep it green and weed-free. Over-fertilizing is all too easy, leading to accumulation of excess nitrates and phosphates in ponds and rivers via stormwater runoff. Pesticides and herbicides reduce biological diversity and interfere with the full functioning of the food web—not to mention the risk many of these chemicals pose to human health.

    Mowing the lawn is another environmental “don’t,”  because gas-powered lawnmowers are heavy polluters and inefficient users of fossil fuels.

    Then there’s the privet hedge. Privet (Ligustrum species) is a nonnative genus of shrubs introduced to North America as early as the sixteenth century. It’s popular because it takes well to shearing, and its leaves contain a chemical that inhibits insects’ digestion. 

A privet hedge marks the boundary of this property

Birds eat the black fruit and distribute the seeds, allowing privet to escape into the wild, crowding out native plants in fields and forest gaps.

    People are still installing this classic formula of lawn and nonnative shrubs, but there’s a trend toward a more sustainable approach. One of my neighbors, Doris Lewis, is a front yard revolutionary. There’s no lawn in front of her house at all. When the house was built, she designed a beautiful combination of trees, shrubs, perennials and groundcovers that make a lovely vista for passersby. It’s much lower maintenance than a grass lawn and doesn’t require mowing, chemical fertilizer, or pesticides. 

Doris incorporated roses and small trees in her front yard design

    Short of Doris’ radical rethink, there’s an incremental, sustainable-enough approach to the front yard that I’ve tried to embrace. It involves minimizing lawn, avoiding use of landscape chemicals, and planting native substitutes for problematic nonnatives such as privet. At present I have no front lawn, and I’m starting to integrate some native plants to liven up the boring shrubs in front of the house. 

An oak leaf hydrangea (Hydrangea quercifolia) is a new addition to the front yard

I notice that some neighbors are trimming away lawn to plant insect-friendly perennials and shrubs too.

    If your front yard is sunny, there’s another way to go. A friend who was part of the local food movement told me that when she saw a front lawn, she thought of it as wasted space for growing vegetables. I’m not aware of front yard vegetable gardens in my neighborhood, but I know they’re thriving in other areas. 

Raised beds in front of the Becker School in Austin, Texas

I recently heard a determined urban gardener describe successfully growing cucumbers right next to her parking spot at the front of her house, inspired by what she considered the outrageous price of organic cukes at Whole Foods. That's the wave of the future.