Gardening for Climate Change

Have you noticed that spring is coming earlier, that plants are blooming at odd times, or that rains are more intense? If so, it’s likely you’re witnessing the first stages of climate change – and how we plan and manage our gardens will have to change. More and more scientists agree that we’re locked into a global temperature increase of 2 degrees Celsius, which is a number we’re told we can’t cross in order to maintain our planet’s equilibrium.

Such a large issue as this can seem overwhelming, and we might tend to feel powerless. But as the climate shifts unpredictably, we can do more than we realize, because even the way we landscape our homes and businesses greatly influences our carbon footprint. We know that burning fossil fuels to cool our homes or mow our lawns releases mass amounts of carbon into the atmosphere, which accelerates climate change and affects how species live in our gardens and wild spaces. What are some strategies to use while designing your landscape that can mitigate energy use and carbon footprints, and help species adapt to climate stress?

Plant Trees and Shrubs Strategically

The majority of a building’s energy use is in cooling and heating, and well over 50 percent of our nation’s energy comes from burning fossil fuels. We can reduce our carbon footprint by employing plants to cool and even warm our home. Deciduous shade trees planted on the south and west sides of structures can cool our homes by as much as 10 degrees in the summer, while a shaded surface may be 20 to 45 degrees cooler to the touch.

Shade trees also lower the air temperature around them 2 to 9 degrees via evapotranspiration; for example, a mature tree with a 30-foot crown will lose 40 gallons of water to the air each day. Even vines growing on a wall can reduce surface temperature by 10 degrees, helping to reduce cooling needs, and a green roof of 3,000 square feet can decrease energy use by 3 to 10 percent. In winter, conifers placed on the north side of a home can block the wind, helping to reduce the energy needed to heat an interior space.

If you want to learn more about strategic planting to reduce energy use, check out Sue Reed’s book “Energy-Wise Landscape Design.” But what else can trees do? They can sequester carbon – literally cleaning and scrubbing the air. Hardwood trees like oak and hickory can store 10 to 40 tons of carbon over their lifetimes. Even flowers and grasses can help – Dayton International Airport’s 600-acre prairie stores 66 tons of carbon each year, locking it away in the soil as the deep roots stretch a dozen feet underground.

Use Adaptable Native Plants Amid Weather Extremes

We’re going to experience more early springs and late springs, record-breaking rains and long-lasting droughts, and the traditionally-pampered garden will suffer. One superb benefit of using native plants in our landscapes is their higher tolerance for climatic stresses – in other words, they tend to be designed for boom-bust cycles.

In the face of a drought, some native plants will close up shop early hoping next year is better, while others won’t be fooled into emerging early when the spring heat comes ahead of schedule. It’s also important that native plants come from open-pollinated seed with local origins, which will make them genetically predisposed to thriving in your area. Another role native plants play is in buffering climate change when it comes to supporting species diversity. For example, many pollinators (moths, butterflies, bees) have evolved special relationships with many native plants. Lots of our native bees species forage for pollen on specific plant species, syncing their lifecycle around the expected bloom time of those species.

Butterfly and moth caterpillars also have specialized relationships with plants, able to eat only specific plants – like monarchs and milkweed or the endangered dotted skipper, which lays eggs on switchgrass. Kids growing up today see 35 percent fewer butterflies than their parents did 40 years ago, and 28 percent fewer songbirds; using native plants will better support wildlife as their environments shrink and morph in a changing climate. In fact, climate zones are moving north and uphill at 3.8 feet per day, but not all species can move, or move fast enough to keep pace.

Adopt a More Naturalistic Landscape Style

Right now our cities and neighborhoods require high chemical and mechanical inputs to look the way we desire. This aesthetic includes lawns that need frequent watering, fertilizer, and mowing, and garden beds that need trimming and weeding with large amounts of wood mulch. One lawn mower emits the equivalent pollution of 11 new cars over the course of an hour, and a two-stroke leaf blower 299 times the pollution of a Ford F-150 truck.

Lawns are the number one irrigated crop in the U.S., and the fertilizer we put on them, far more often than the grass needs, also requires massive amounts of energy and fresh water to be produced. If we can mimic at home how wilder areas function, we can save ourselves a lot of work, money, and fossil fuel use.

Removing some lawn and designing thicker garden beds with evocative layers of plants – from groundcovers to ornamental grasses to shrubs and trees – will shade out weeds and eradicate the need for wood mulch, all while sequestering carbon and cooling the air. This naturalistic design – one that emulates how wilder nature works – will also support more wildlife, like bees and butterflies who have coevolved with plants, and the 96 percent of bird species that feed insects to their young. Thick gardens also support beneficial predator bugs and spiders, which reduces the need for pesticides and other chemical inputs in our landscapes that pollute the soil, water, and air.

Your garden can make a significant difference in the fight against climate change. We can use trees, shrubs, and vines to shade our homes and reduce energy use while sequestering carbon from the air. The plants we choose can be composed largely of natives, which are genetically hardwired to tackle local weather extremes. And lawn-reducing planting beds that are thick and lush, just like we’d see in nature, make added contributions to minimizing carbon footprints while providing essential habitat for diverse wildlife.