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Sunday, July 31, 2016

Dry and thirsty

The recent heat wave following on a months-long drought displays the many mistakes I made regarding water when I designed my garden. In hindsight, it’s easy to see better choices I should have made.

    Most basic was plant choices. Xeriscape, a water-conscious approach to garden design, provides guidelines for selecting plants that don’t need supplemental watering. Some tips: smaller leaves generally need and lose less water, grayish or fuzzy foliage usually means a plant is drought-tolerant, low-growing plants avoid drying winds, and plants with a scent, such as lavender, produce aromatic oils that help plants hold onto water. I did end up with some plants with each of these characteristics, but not out of any conscious plan.

Gray, fuzzy leaves of lambs' ears (Stachys byzantina) conserve water

    Next, I should have grouped plants based on their water needs. Putting thirsty hydrangeas next to water-sipping catmint, with its small gray leaves, might have looked nice, but it meant I under-watered the hydrangeas and probably used more water on catmint than it needed—though it didn’t complain.

Hydrangeas need a lot of water

    Then there was my choice of irrigation method.

Sprinklers lose water to evaporation

The sprinkler system we installed was standard for our city, but I could have saved on evaporation by using soaker hoses, which sweat droplets of water, or drip irrigation, with small emitters that deliver water precisely to the spot its needed at the base of a tree or shrub.

    My rain barrel is a small step toward collecting rain to irrigate the garden. 

The rain barrel is great--when it rains

I wish I’d thought to install an underground cistern to store all the rainwater that falls on the roof before I planted my garden. If I had, in an average year the cistern could have supplied my garden’s irrigation needs. This is certainly not an average year, though. To irrigate with rainwater, you have to have rain, and this year that’s been scarce.
    So at this point, my garden is looking sad and parched. 

A forsythia wilting outside the range of the irrigation sprinklers

With a guilty conscience, I supplement scheduled irrigation from the sprinkler system with evening use of a rotating sprinkler to revive wilting plants in areas the automatic system misses (evening watering is recommended to minimize evaporation). 

     We get our water from the Quabbin and Wachusett reservoirs in western Massachusetts, and our water authority hasn’t imposed a watering ban so far. Not so lucky are gardeners whose water comes from town supplies, nearby rivers, or wells on their own property. I can only imagine how painful it would be to watch cherished plantings die from lack of water.

    If I ever build a new house, I’ll put in that underground rainwater cistern before I start planting, and I’ll push for a graywater system too. That would collect water from sinks, dishwasher, clothes washer, and shower to reuse for irrigation. The city of Las Vegas has this all worked out long since. 

     In the meantime, I’ll make sure I dump water from the sink on garden beds when I can instead of letting it flow down the drain, and I’ll think about less lawn and more drought-tolerant native plants for next year.

Cucumbers on the deck benefit from any spare water from the sink

Sunday, July 24, 2016

Invasives are here to stay

I hate to say this, because I think it will make some people mad, but I don’t think there’s any hope we can eradicate invasive nonnative plants from our landscape.

    This is an area of hot controversy. Many admirable volunteers spend their weekends pulling out invasive plants that grow on public land. 

Volunteer at a garlic mustard pull in Washington state

These are plants that cause environmental damage, out-competing natives and endangering local insects and animals because they don’t provide them with food and shelter they need.

    People who devote their time to eradicating invasives reject tolerating these plants. But there is another perspective. As Hope Jahren points out in Lab Girl, “Humans are actively creating a world where only weeds can live and then feigning shock and outrage upon finding so many.” Cities are hotter, dryer and windier than the countryside they replace, and we keep tearing up the ground with new building projects. No wonder only the toughest plants survive.

    Even if public land were cleansed of invasives, it doesn’t exist in a vacuum. At the Garden Bloggers Fling in Minneapolis, I heard that the Eloise Butler Wildflower Garden  had to have volunteers scour garlic mustard (
Alliaria petiolata) from a buffer zone around the 15-acre garden to keep it from migrating into the reserve. Yet every year their staff still has to patrol the property for garlic mustard seedlings. 

Native black-eyed Susans and bee balm at Eloise Butler Wildflower Garden

    Garlic mustard crowds out other herbaceous plants and excretes antifungal chemicals that disrupt connections between soil fungi and native plants, suppressing growth. 

Garlic mustard in bloom

What is the chance that every Newton homeowner will police her property and catch every garlic mustard plant before it sets seed? Not since Maoist China has social engineering on that scale been feasible.

    Here’s a case in point. Across the street from my house, a neighbor’s fence runs parallel to the sidewalk. In the few inches of soil between the fence and the pavement, a panoply of invasives has taken root. There’s garlic mustard, Oriental bittersweet (
Celastrus orbiculatus), Norway maple (Acer platanoides), and black swallowwort (Cynanchum louiseae). Yes, I uproot them as I walk by. But all over town the same situation is occurring, and in most places no one notices or cares.

Oriental bittersweet

Norway maple
Black swallowwort
So if we can’t kill all the invasives, what are we supposed to do? Are we willing to let them take over and accept simplified landscapes without the biodiversity needed to maintain native animals? 

Actually we already have. A stroll in any local park confirms the presence of large populations of invasives. 
     I may be unrealistic, but I prefer to think that by planting natives in our own yards and fostering their growth on public lands, we can restore some balance between natives and aggressive nonnatives. If not, we’re going to spend all our gardening time at war, and that’s a condition I can’t accept.

Native red oak in my yard. This is a popular host plant for native insects

Sunday, July 17, 2016

Planting for pollinators in Minnesota

I’m in Minneapolis experiencing the Garden Bloggers Fling, the ninth annual gathering of garden bloggers from all over North America. We’ve been privileged to visit glorious public and private gardens. So much beauty has been almost overwhelming!

Yellow and orange border at Lyndale Park Gardens

Many of the gardeners who have invited us into their gardens are doing great work planting for pollinators. I was wowed by the garden of Rhonda Fleming Hayes, author of Pollinator Friendly Gardening. I especially loved the raised beds she filled with striking combinations of vegetables and ornamentals, a far cry from any vegetable garden I’ve ever imagined. Insects were happily buzzing and flitting around her lush plantings.

Rhonda's intensive mix of flowers and vegetables

    We toured gardens of Master Gardeners in Minnetonka. One of our hosts, Ruth, had done prodigious work clearing out buckthorn, a nonnative invasive shrub. She had planted native shrubs, trees and perennials that will soon fill in to make a paradise for native insects and other animals. We could already hear how happy the birds were in her yard.

    Also on the tour was the garden of Laura and Steve, who maintain a piece of property behind their house as an unspoiled wetland to protect wildlife. Their yard was a shade garden after my own heart. I realized how soothing I find greens in different shades and textures, with a few flowers as accents. They too had chosen many native plants.

Subtle shade combination in Laura and Steve's garden

    Saturday night we heard a poignant talk by Peggy Anne Montgomery of American Beauties Native Plants, one of the sponsors of the Fling. Peggy Anne spoke about the threat to pollinators from pesticides and loss of habitat. She reminded us that we can help remedy this in our own gardens by planting some beautiful native plants. 

    Peggy Anne pointed out that lots of flowers can provide nectar and pollen for insects, but most insects are specialists that need particular host plants to eat and reproduce. A familiar example is monarch butterflies, which need milkweed. The adult females lay their eggs on milkweed plants, which the caterpillars need to eat.

A monarch at Vera's Garden, a community garden along the Midtown Greenway

    As Peggy Anne pointed out, without milkweed, there will be no monarchs. She urged us to plant host plants for native insects. Her talk will prompt me to think beyond flowers to insects’ other life cycle needs.

    Tammy Schmitt, who blogs at Casa Mariposa, warned that annuals from garden centers can be permeated with commonly used insecticides called neonicotinoids. These are particularly toxic to bees. Tammy grows her own annuals from seeds to avoid bringing the neonicotinoids into her pollinator garden.

    I’ll return home inspired to find more ways to make habitat for pollinators in my own garden. I’ll get some help from mountain mint (Pycnanthemum muticum), a gift from Peggy Anne and American Beauties Native Plants. Peggy Anne said she’s never seen so many insects attracted to one plant. I can’t wait to see what this plant will do in my yard.

Sunday, July 10, 2016

Tough goodbyes

It’s a plant, not a pet, as Kerry Ann Mendez reminds us in her book The Right-Size Flower Garden. A rational gardener should be able to throw away any plant that’s not doing what she wants it to do. Perhaps it’s grown too big, the flower color isn’t what you wanted, it’s turning out to be aggressive, or maybe it’s just failing to thrive. Failure to thrive in humans is a reason for a hospital stay. In plants, it means it’s time to throw the sad sack on the compost pile.

Discards in the compost bin

    Although my rational side knows this makes sense, I get attached to plants. Some of my houseplants have lived in the house as long as I have. They seem like part of the family. How could I have the heart to discard them?

    This summer as usual I have to force myself to throw away some plants I can’t use. One of my container staples is elephant ears (Colcasia esculenta). In summer my New England landscape starts to look blah, with all the deciduous leaves around the same size and color. The huge light green leaves of elephant ears, up to two feet long and almost as wide, add some much-needed drama to the yard after the spring flowers have faded. 

Elephant ears add a bit of tropic flair

    Otherwise known as taro, this plant was one of the first crops cultivated by humans. It’s easy to grow in tropical areas of Africa and South Asia, where the fleshy roots provide a useful starch. It multiplies just as easily for me, and at the end of the summer I often have more elephant ears plants than I had the previous spring. This year I’ve used all I can in containers. I’ve got three burgeoning specimens left that I’m going to have to discard. It hurts.

    Then there are the plants that are sick or dying. This weekend I admitted that two of my African violets were probably never going to do well. 

I kept hoping these African violets would fill in

If I were willing to try, I might be able to rehabilitate them by cutting off the stems and re-rooting them. I’ve got more than I need already, though, so it’s time for these to go. Another sad parting.

    I took the pruners to the variegated kiwi (Actinidia kolomikta) that’s been growing against a north-facing wall along the driveway for at least twenty years. It’s made it through a lot of hard times, but now it’s infested with scale for the second year. I don’t want to use pesticides, beyond removing each insect with a cotton ball soaked in rubbing alcohol. So I’m going to try replacing it with a native honeysuckle (Lonicera sempervirens). 

    I cut the poor kiwi off its supporting wires to send out as yard waste, making sure to pick up any infested leaves that fell to the ground. 

Kiwi vine in the yard waste. The cottony white blobs are scale insects

A lot of memories go with that vine. I hope the honeysuckle will live a long and scale-free life.

Honeysuckle blooming near the ill-fated kiwi. This native vine is tough.

Monday, July 4, 2016

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.