Let's start the new year with some good news! We are constantly bombarded with bad news, most of which we can do little about. So here's the good news — by using sustainable practices in our gardens we can positively influence the world around us. And whatever we do to reduce the negative impacts of gardening on the larger environment results in healthier gardens.
Furthermore, the elements of sustainable landscaping reinforce each other, creating positive feedback loops. And finally, these practices sustain us as well, enriching our lives with a stronger sense of place and the rewards of being attuned to natural processes and seasonal patterns. The California Landscape Garden eloquently comments: "... as we work in our own gardens to heal the larger California garden, we are ourselves healed and restored by a personal habitat that is full of life and ecologically robust ... ."
What is sustainable landscaping? Here's a definition I like: landscaping that creates a regenerative cycle that is tied into the larger ecosystem and that requires minimal external inputs. In this column I will discuss one of the key concepts of sustainable landscaping: promoting biodiversity — the flourishing of a wide range of plant and animal life. Sustainable landscaping promotes biodiversity in several ways.
Using Native Plants
Using native plants in gardens is an important element of sustainable landscaping. Our local native plants are unique, interesting and often very beautiful. They are also well-adapted to local climate and soil conditions. And, very importantly, they provide habitat for native birds, bees, butterflies and other insects. Ecologists estimate there are roughly 20 animal/insect species associated with each native plant species. If you want to sustain native wildlife, you are well advised to include native plants.
Want to learn about local native plants? Check out the website for the North Coast Chapter of the California Native Plant Society at www.northcoastcnps.org or go to www.calscape.org and type in your address to be provided with a list of plants specific to your area.
I am not suggesting that you should plant nothing but natives. I appreciate the approach advocated by Ann Lovejoy, a prominent Seattle-based garden writer, who recommends that gardens should be a mix of natives and what she calls "allies" — that is, plants that thrive under the same conditions as natives.
Avoiding Invasive Plants
However, there are some non-native plants you should definitely avoid: plants that are listed as noxious invasive weeds in our area. These include known problem plants such as Scotch broom and pampas grass but also popular garden plants such as English ivy, cotoneaster, holly, periwinkle and even foxglove and butterfly bush. The Humboldt County Weed Management Area team has compiled a helpful booklet detailing why these plants are so problematic, how to identify them and how to get rid of them. You can find the booklet online at www.cal-ipc.org.
Many songbirds, bees, butterflies, frogs, toads and bats are threatened or critically endangered. Sustainable landscaping provides habitats for these creatures. There are abundant sources of information on gardening for wildlife and a common refrain runs through all of them: Avoid insecticides, herbicides and fungicides, grow native plants, utilize a wide variety of plants that bloom throughout the year, provide shelter in the form of rock, brush or wood piles and offer a source of water (for bees and butterflies, even a small patch of moist soil). Remember that when we invite these creatures into our garden we reap the benefit as well as they provide color, sound and movement, literally animating the landscape.
A few bee facts: In addition to honeybees (which are not native) there are 1,600 species of native bees, most of which are solitary bees as opposed to social bees living in colonies. Native bees pollinate about one-third of our vegetable, fruit and nut crops and almost all of our wildflowers. Native bees are hardier than honeybees and can fly at lower temps. A majority, 60 to 70 percent, of native bees are ground nesters, so leave some patches of bare soil in the garden. Researchers from Humboldt State University have tallied 40 native bee species in our coastal dunes and 100 species in the local mountains. And, a University of California study found that California native plants are four times more likely to attract native bees than non-native plants.
Adult butterflies feed on nectar from flowers but butterfly larvae feed on the plants themselves — with roughly 80 percent of the larvae having very specific requirements in terms of what plants they can eat. For example, monarch butterfly larvae feed only on milkweed plants. So, in order to support future generations of butterflies, we need to provide both larval host plants and to tolerate a certain amount of damaged foliage.
Minimizing or Eliminating Nonfunctional Lawn Areas
Lawns offer important play spaces for children and adults and a small lawn can serve as a pleasant visual contrast to a surrounding array of plantings. However, lawns do not promote biodiversity and large areas of lawn that do not serve a functional purpose can be environmentally problematic due to high water usage, hazards from the use of lawn chemicals and fertilizers, and the fossil fuels and noise pollution associated with lawnmowers, edgers and blowers. Consider converting a lawn that isn't being utilized into a pollinator garden, a woodland sanctuary for birds or a vegetable/fruit garden.
My next column will focus on other important aspects of sustainable landscaping such as water conservation and minimizing the need for fertilizers and pesticides.
Donna Wildearth is the owner of Garden Visions Landscape Design in Eureka. Visit her website at www.gardenvisions.biz.