Ecological gardening

 While snow blankets the garden, it’s all potential. Dreaming of spring, I’m enjoying reading about ecological gardening—what I’ve been calling sustainable gardening, but I like the new term better. As Kelly Norris writes in a recent article in Fine Gardening, ecological gardening means understanding plants as part of a community, not just building blocks for an aesthetic composition.

 

Native Joe Pye weed in an ecological garden

    Goals I currently aspire to achieve in my ecological garden include promoting and supporting biodiversity, helping to keep air and water clean, sequestering carbon, minimizing my garden’s carbon footprint, conserving water, and preventing stormwater runoff. Since these are inherent functions of natural systems, the good news is that gardening this way should be less work, not more.

 

Leaf mulch conserves soil moisture and provides shelter for native insects

 
    Native Plant Trust and the Woodwell Climate Research Center have been researching how these goals can be accomplished in suburban yards in their Yard Futures Project. They’ve chosen yards in six cities: Boston, Baltimore, Minneapolis-St. Paul, Phoenix, Los Angeles, and Miami. The lucky chosen ones get a visit from a team that’s prepared to observe and document what’s living on their property, from birds to insects to soil organisms. The goal of the research is to document the current state of backyards in a range of climate conditions and discover how suburban properties can best support a healthy environment.

    I wish my yard had been chosen! I’d love to know what experts could find there. In one visit, they could detect and document far more than I ever will. But I’m hopeful that my yard would show lots of biodiversity, because I’ve been trying to put out the welcome mat with native plants and gardening strategies that imitate natural processes.

 

Virginia bluebells

    To take it up a notch, I can start to think more about how plants weave together in natural settings. For example, when choosing a perennial, I pay attention to whether it’s a spreader. That might be a red flag for a traditional garden, but for creating a ground cover layer in a naturalistic ecological garden, it can be an asset. But I don’t usually ask whether a plant is tap-rooted or rhizomatous, grows singularly or in colonies, is short- or long-lived.

 
     In nature, plants fill every available space, above ground and below, gaining from each other’s contributions and maximizing diversity. Instead of fields of mulch punctuated with separated plants, ecological gardens are a mix of tall and short, broad and upright, early and late-developing plants, similar to what you’d see in a wild setting.

 

Plants knit together in an ecological garden

    This doesn’t have to look like a mess. By maintaining clear edges and growing large swathes of species that flourish in site conditions, ecological gardeners are creating gardens that are “legible”—appealing to viewers as designed spaces.

    So for this spring and summer, I’m thinking about how to fill up beds with more—more low spreaders, more early bloomers for the first pollinators of the year, more self-seeders. They should be native plants, but that’s not all. They should contribute actively to the plant community.

 

For the pollinators

 

 

 

Live and let live

This month Bayer agreed to pay $10 billion to people who’ve developed cancer after using Monsanto’s herbicide Roundup. Bayer plans to continue selling Roundup and still insists that it’s safe to use. The record settlement suggests otherwise. And there’s a huge environmental drawback to Roundup that doesn’t get enough attention: loss of biodiversity.

    The active ingredient in Roundup is glyphosate, which blocks the action of an enzyme that allows plants to make a necessary amino acid. 

Roundup at Home Depot

Roundup has been around since 1974, but it became a huge moneymaker in 1996 after Monsanto introduced Roundup Ready crops. These are patented genetically modified plants in which the target enzyme isn’t affected by glyphosate. More than 90 percent of US soybeans are now grown from these genetically modified seeds. Roundup is so ubiquitous that super-weeds have developed resistance to glyphosate.

Soybean field, Pennsylvania-photo Jakec

    When my garden was young, I remember being taught that while other herbicides might be dangerous, Roundup was perfectly safe. The idea was that it breaks down so fast that residues in plants and soil wouldn’t be a problem (not true).

    The most important reason to avoid Roundup, I think, is that spraying weed-killer in yards or on agricultural fields eliminates a huge reservoir of native plants—the weeds—that native insects depend on. A good example is the loss of common milkweed (Asclepias syriaca) that monarch butterfly larvae depend on. With widespread Roundup spraying, monarch populations have plummeted. 

Monarch nectaring on common milkweed

     Full disclosure: I once tried spraying Roundup when I saw the notoriously aggressive groundcover goutweed (Aegopodium podagraria) spreading around plants I’d received from a friend’s garden. 

Goutweed can easily get out of control

I planned the Roundup application for a sunny fall day. It took me two hours, because I was so fearful. I put on old clothes and sneakers, disposable gloves, goggles and a mask. 

 

I wished I had this much protection when spraying Roundup

I covered the surrounding plants over a radius of at least a yard with rags, then I carefully sprayed Roundup, trying my best to wet only the goutweed foliage. Then I had to remove the rags and protective gear and throw my clothes into the washer.

     Was it worth it? Not at all. The goutweed never missed a beat. Perhaps I’d applied Roundup too late in the season when the plants had stopped growing. The next spring, I weeded the goutweed out of the bed, taking extra care to dig out its slender roots. It never reappeared.

     As nonnative invasive plants became a focus of concern, Roundup was touted as a solution. Painting Roundup on cut stems of bad actors like Japanese knotweed (Polygonum cuspidatum) is still recommended. That’s understandable, because the plants are virtually immortal. I tried it once with no effect. The knotweed sprouted again the next spring. For my purposes, the benefits of Roundup definitely don’t outweigh the risks. Now I prefer the idea of hiring a flock of goats to eat knotweed thickets.

A goat clearing invasive plants at Travis Air Force Base-U.S. Air Force Photo by Heide Couch

 
     If we had a functioning federal government, it would ban glyphosate as well as neonicotinoid insecticides. Us against them isn’t a sustainable way to think about natural systems.

Sustainable enough

I just listened to an informative interview with Uli Lorimer, director of horticulture at Native Plant Trust, our local native plant society in Framingham, Massachusetts. Uli was a guest on garden writer Thomas Christopher’s weekly radio show and podcast, Growing Greener. Thomas focused the interview on native and locally adapted plants.

Monarch on New England aster

    Together, the two men proposed a type of garden that’s designed to serve the interests of as many living things as possible, not just humans. Instead of choosing plants because they’re pretty, you’d select what performs the most useful functions for your garden ecosystem. You’d put aside neatness as a top aesthetic priority.

Goldenrod is a key player in this meadow ecosystem in Maine

    This is the path I want to follow, but I argue that we don’t all have to arrive right away. Uli pointed out that much important information about native plants hasn’t yet been ascertained, and the rest hasn’t spread past native plant enthusiasts. As a start, he suggested, growers should be using plant labels to tell where plants came from and how they were propagated.

A plant label that lists the seed source and nursery location

    Native Plant Trust advocates growing plants that evolved in the local ecoregion, the area with the same environmental conditions they'll find in your garden. In addition, they value genetic diversity within each species, meaning plants that are grown from seed, not cloned through cuttings or divisions to be genetically identical. 

    A genetically diverse, locally adapted plant population will be well-equipped to deal with shifts in its environment, including rapidly changing climate. But so far, conventional growers haven’t figured out how growing from seed could be scaled up to their volume of production in a financially viable way. In addition, we consumers have been trained to want reliably uniform plants, which is what you get with clones. Seed-grown plants are variable. 

Mass produced plants are genetically identical and uniform

    Native Plant Trust sells about 300 species of locally adapted native plants at their garden shop. They’re grown from ethically collected wild seed of known New England provenance. But what if the shop doesn’t offer a native plant you’d like to buy? Is it wrong to buy plants that don’t meet their high standards?

    This brings me to my point. I think becoming a sustainable gardener, and a native plant gardener, can be a process. You don’t have to change everything all at once. After 35 years, my garden is full of nonnative plants I’ve chosen over the years. Many of the ones that have survived are plants I love and wouldn’t dream of removing. We have a history together.

They'll have to pry my nonnative white bleeding heart from my cold dead trowel

    Every year as I learn more about native plants, I add more of them to the garden. I adjust my gardening approach to accommodate their needs and welcome a richer population of wildlife, especially insects. Is it still OK to buy nonnative plants because you like them, or North American native plants even if they’re not local, they’re “improved” cultivars of native species, or they’ve been propagated asexually? I think it is. If we’re thinking about these issues, we’re moving toward full sustainability, even if we’re not there yet.

Newly planted mountain mint from NPT--native, locally grown and adapted

 

Snowdrop clones

Snowdrops (Galanthus nivalis) are blooming in my front yard, a hopeful harbinger of spring. From the flower’s point of view, what’s the point of blooming so early? I read that bumblebee queens, who survive for several years, may emerge early enough to pollinate these very early flowers, allowing them to set seed, as they would in their home range in Europe and Asia. 

Snowdrops have slowly formed clumps in the front yard

    But the expanding clumps of snowdrops in my garden are most likely clone colonies, groups of connected individuals whose genetic material is identical. Since they’re rarely able to produce seeds, they spread vegetatively as their bulbs reproduce underground and send up new plants.

Snowdrop bulbs can divide and make offsets-www.BioLib.de

    Snowdrops aren’t the only plants that increase this way, of course. The biggest clone colony in the world is a grove of quaking aspens (Populus tremuloides) in Utah called Pando, reputed to be the world’s largest living thing and one of the oldest. 

Pando in fall-the whole grove is one giant organism

Pando covers 106 acres, with about 40,000 genetically identical trunks growing from the shared root system, which is about 80,000 years old. When wildfires kill the trees above ground, the roots survive. Another venerable giant clone colony is the King Clone creosote bush (Larrea tridentata) in the Mojave Desert. 

     In my own yard I’ve got more modest colony formers such as pawpaw (Asimina triloba), sweetshrub (Calycanthus floridus), and highbush blueberry (Vaccinium corymbosum). 

Pawpaw sends out roots to form a clonal clump

    As we recall from high school biology, when two individuals get together to reproduce, their genes are mixed together in the process of meiosis. That gives each of their offspring a unique combination of genes, half from each parent. Colony formers spread asexually by mitosis--plain cell division--passing on the same genes to new individuals, which are clones of their parents. That doesn’t mean their genes never change, because mutations occur spontaneously over time. But the colony has mostly the same genes repeated over and over.

These snowdrops are genetically identical

    As much as I love seeing the clumps of snowdrops emerge from the leaf litter or the snow, I’d rather that most of my garden plants be more sexually active. When individual plants within a species differ genetically, a diversity of traits will give the species a better chance of coping with predators, disease, and climate change.

Potatoes blighted in the Irish Famine were clones without diverse defenses-USDA

    This is another reason to buy straight native plants rather than cultivars for my planned pollinator bed. Once a nursery spots a desirable flowering plant as the basis for a cultivar, they reproduce it asexually by cuttings, divisions, or tissue culture. They want new plants that are genetically identical to the desirable ancestor. Straight native species grown from seed, on the other hand, come from open (uncontrolled) pollination by insects, birds or wind. They’ll add biodiversity to the garden.

Open pollination supports genetic diversity

    Currently cultivars dominate the market. Sometimes even native plant nurseries have to offer plant selections or varieties that are truest to their species, because no straight natives are available. Let’s hope that will change as demand for native species increases.

I could only find a cultivar of this scarlet beebalm for sale, so I chose another species in the genus

Shrinking the lawn

Evelyn Hadden’s book Beautiful No-Mow Yards recently reminded me that I still have a grassy lawn. The book spotlights gardeners around the country who have dispensed with lawn, replacing it with options ranging from groundcover beds to meadow gardens to paths leading between garden “rooms” full of beautiful perennials, shrubs and small trees.

Native perennials replace lawn in Robin Wilkerson's garden in Lincoln, MA

    While I’ve long aimed to eliminate lawn, I realized that I’m not ready to give up grass completely. What I’d like would be to reduce it to an area of transition between beds. I still like the look of the visually quiet mowed surface as a foreground for other more exciting plants.

Lawn makes a nice foreground

    Even a low-input lawn like ours is environmentally undesirable. Our lawn uses fossil fuels for mowing, but it’s getting by without fertilizer, weed-killers, or extra water. It’s still a pretty barren habitat for native insects and birds, compared to other ways garden space can be used.

    My lawn-reduction effort started back in the 1980s when I replaced a part of the front lawn with vinca (Vinca minor, also called periwinkle). That wasn’t so much a principled choice as an acknowledgment that grass wasn’t going to grow under the shade of the Norway maple street trees. The groundcover bed has proved to very low-maintenance, needing only occasional weeding to remove maple seedlings.

Vinca groundcover beds are neat and easy to maintain

    Next I dug out some grass around a fish pond we’d installed in a circle of lawn in the backyard. I planted perennials and dwarf trees instead, including two dwarf blue spruces (Picea pungens) that I particularly like. As they slowly enlarge, I’ll need to decide whether to move them and choose something smaller. Meanwhile, they’re doing their part by filling what would otherwise be lawn and offering shelter for moths and butterflies.

Perennials and blue spruce replace some lawn

    Two years ago I took out a big chunk of lawn when I created two perennial beds off the back deck. That and a bluestone path eliminated about 600 square feet of grass. While we had school-age kids, we wanted an open space outside the back door where they and their friends could run around. Now it’s nicer to turn that space over to flowers and pollinators, especially because it’s one of the sections of the yard that gets the most sun.

 

New beds and path where lawn used to be

    Last March I added to a bed with a sheet-composting project. As you can see, the mound of wood chips and compost is starting to settle. With continuing decomposition, after two years, it should sink to the level of the surrounding lawn. Then it will provide a rich environment for flowering perennials. I’m planning to move some there from places that have gotten too shady. If there’s space left, I can add new ones too.

Sheet composting mound is subsiding

    My next plan is to repurpose some lawn space across from the sheet composting. Outside the vegetable garden fence, I could create a cutting garden. It would be nice to grow dahlias, zinnias, and snapdragons just for enjoying indoors in a vase. Why not?

Wouldn't flowers look better?

Nature: it's right here

It’s frequently said that people can achieve mindfulness, access tranquility, restore emotional equilibrium, and enjoy a host of other benefits by being “in nature.” 

Nature writ large-photo NPS

This prescription always troubles me. I know what people mean: they like to visit the forest, the mountains, the seashore, or whatever wild landscape is their spiritual home when they’re feeling troubled or overwhelmed. That’s healthier than a lot of the choices that may beckon when you want to make yourself feel better.

    My problem is with the idea that you have to go someplace special to be “in nature.” Nature is everywhere. I admit that I usually envision nature as outdoors. It’s indoors too, and even inside our bodies, as demonstrated by recent revelations about the gut microbiome.

Microbes are part of nature too-image USDA

    You don’t have to fly to a natural park or drive to your local conservation area to find nature. When I’m traveling around a scruffy town near Boston for work, I’m cheered by evidence on every block of plants taking back territory from the barren landscapes constructed by humans. Seeds fall into cracks in the sidewalk. Roots push their way from the curb strip or front yard to the next patch of open soil. To my mind, those pioneers count as nature too.
 

Spontaneous and beautiful

    There’s a problem with defining nature as just what you find in seemingly pristine wilderness areas. It’s important to conserve the last areas of virgin forest, unspoiled seashore, and underwater habitat. But if we insist that nature exists only where there’s no human footprint, we’re leaving out most of the world’s ecosystems. We need to support biodiversity even in cities and suburban areas. 

    The movement to plant native plants and pollinator gardens is worthwhile because it’s possible for humans to live comfortably alongside plants that restore habitat for animals, especially native insects. A New England gardener including some bee balm (Monarda didyma), Joe Pye weed (Eutrochium maculatum) or aster (Symphyotrichum novae-angliae) in her garden enables a small increase in biodiversity. 

Cosmos in the curb strip supports native insects

All the yards together can do a lot, even when native plants don’t predominate in every garden. If we think the suburbs aren’t part of nature, though, we won’t see that we have a part to play.

    As effects of global warming progress, we urgently need to bolster ecological services provided by plants, such as cooling, air purification, and carbon sequestration. Street trees, long-lived plants in our yards, or even a few shrubs or small trees in concrete planters in a city center all contribute toward combating the effects of climate change. 

A street tree doing its part

Each tree uses the same natural processes plus water, air and the sun’s energy to bind carbon in its tissues and the surrounding soil. It doesn’t have to be part of a forest for that to happen.

    We humans are part of nature, and so is our local habitat. That means we need to be good stewards of every part of the world. It also means we’re never marooned outside nature, which is a thought I find comforting.

I'm off to British Columbia. See you in two weeks.

Wall! What is it good for?

One of the many reasons that a border wall is a terrible idea: it’s a design for environmental disaster. Living in the Northeast, we picture the Mexican border territory as a barren desert populated with a few cacti and coyotes. That’s not true at all. The southern border lies in a transition zone from temperate to tropical habitat. In Arizona, New Mexico, and Texas, the border runs through sky islands, mountainous areas surrounded by desert.

 Catalina Mountains near Tucson-photo Brambleshire

 Protected by a chain of wildlife refuges, this varied geography makes a home for an unusually rich mix of species. The border region is one of the most biodiverse areas in North America and hosts more than 180 threatened and endangered species. 

    Sections of wall already constructed have caused serious trouble. 

Border fence restricts movement of wildlife

Dividing animal populations that roam between the US and Mexico creates smaller groups with less genetic diversity, leading to extinction. The wall cuts off water access during the dry season. As climate change progresses, the barrier hampers animals’ ability to adapt by choosing the best locations at each time of year. Even low-flying birds, such as pygmy owls, can’t fly high enough to make it over the wall. 

    The 2005 REAL ID Act permits the federal government to forge ahead on wall construction in the name of national security, ignoring existing laws, such as requirements for environmental impact studies. Crews with chainsaws appeared at the National Butterfly Center, a private sanctuary a few miles north of the border, without warning and tore out carefully chosen plantings fostered over many years. 

Fiery Skipper at National Butterfly Center-photo Bettina Arigoni

These losses will be hard to recover, even if sanity does return to our government. Meanwhile, the 24 million dollars it costs to build a mile of wall could fully fund population recovery of endangered ocelots, jaguars and gray wolves that depend on borderland refuges.

Endangered ocelots need to range freely between the US and Mexico-photo Ana Cotta

    The height of Trump’s fantasy wall varies. It’s been as high as 55 feet. In my town, we don’t have any 18-, 30-, or 55-foot walls or fences. The usual fence is 5 feet tall. My yard is surrounded by wooden fencing. 

This fence looked best when it was new and fresh in 1997

When a small dog came to visit, I noticed that in a lot of places, the fence doesn’t reach the ground, making it easy to slip under. Cats and raccoons regularly climb over the top, and squirrels hop across on overhanging branches. Even so, I wish I hadn’t opted for solid fences. Now I prefer the wood-framed fences filled in with lattice or widely spaced wire that I see in a few places in the neighborhood. 

A more open fencing option

This system creates a formal barrier, but it doesn’t keep migrating plants or animals out. It also looks better. The best thing about my fences is the support they provide for clematis vines.

Grape and clematis vines twining up the driveway fence

    Can’t we find a more sensible way to maintain our borders? As California Congressman Ted Lieu said, a wall is first century technology. It’ll kill endangered animals and ruin pristine wildlife refuges, but it certainly won’t keep out refugees who have nowhere else to go.

Monument to people who've died trying to cross into the US © Tomas Castelazo, www.tomascastelazo.com / Wikimedia Commons / CC BY-SA 3.0

Sex, drugs, and plant propagation

Which is better, sexual or asexual reproduction? It depends who’s doing the reproducing. This spring I’m making new plants both ways. Seeds are produced through sexual reproduction. Each seed has two parents with different genetic make-ups. That means each seed, and the plant it grows into, is a unique individual, like us. I’m growing a lot of my new plants from seed, including vegetables, herbs, and annual flowers.

Each borage and basil seedling is a genetically unique

    Asexual reproduction accounts for a lot of the perennials, trees and shrubs we buy. If you’re a breeder who wants to make sure your dogwood or azalea is exactly like its parent, you clone it. Unlike human tissues (so far), plant tissues have the ability to reproduce whole plants from parts of the parent plant.

A desirable rhododendron can be cloned infinitely

     Right now I’m growing cuttings from last year’s rosemary, bearberry (Arctostaphylos uva-ursi), and coleus. I’m hoping to do the same with tarragon and oregano I bought at the garden center. If these cuttings take root and grow, the plants they grow into will be genetically identical to the parent plant.

Cuttings from bearberry and coleus are clones

I’ve read that some named shrub varieties consist entirely of clones from one desirable plant. Many plants, but identical genes.

    People concerned about biodiversity have a problem with this system. In addition to encouraging us to grow native plants, they want us to foster genetic diversity among plant species. The reason is that a broader gene pool allows a species to adapt to changing environmental conditions. Some individuals in the population will develop greater resistance to heat, drought, flooding, and other challenges. As climate change speeds up changes plants face, they need to be ready to evolve in response.

    There’s an inherent tension between promoting biodiversity and maintaining desirable varieties. If you’re trying to grow a particular tomato, say ‘Brandywine,’ which is open pollinated (not a hybrid), you don’t want your ‘Brandywine’ plants fertilized by pollen from other tomato varieties. 

Tomato growers want to keep varieties distinct

     But if you’re just growing a patch of perennials, say native purple coneflowers (Echinacea purpurea), there’s no reason not to let them mix with nearby members of their species and create a genetically mixed population. In fact, your stand of coneflowers will be more likely to survive if it includes members with different genes that can tolerate varying conditions.

A genetically diverse coneflower population is adaptable

    Except for letting willing self-seeders do their thing, I haven’t propagated perennials from seed. When I want more, I may divide the plants or, as with rosemary, bearberry, and ivy, grow more from cuttings. If a snippet from the growing end of a plant is willing to send down roots, why not make more that way? Divisions and cuttings make clones, just as tissue cultures made by breeders from a few cells grow into clones of a newly-developed perennial. In future I want to learn to grow native perennials from seed so I can help maintain their genetic diversity.

Felix, a new garden helper visiting from New York

I’m off on a trip to the Southeast, hoping to experience spring flowers there and again at home when I return. See you in two weeks.