How to adapt your landscape to a changing climate

Seattle is experiencing unprecedented heat even before the official start of summer. On Sunday, June 8, Seattle-Tacoma International Airport reached a high of 90°F at 5 pm, surpassing the previous record of 87°F, which was set in 1948 and matched in 2015. The overnight low was also notable, with temperatures only dropping to 61°F, breaking the old record of 60°F from 1948. The heat persisted into Monday, when the high reached 87°F.

Changing climate

While short heat waves aren’t unusual, the overall climate is shifting. “Normal” weather is more elusive. And that affects how we plant and care for our landscapes.

Our summers are now consistently hotter and drier, often with prolonged drought. Winters bring heavier rain and wind, severe snowstorms and dangerous ice.

According to The Climate Change Garden, the challenge isn’t just changing climate patterns. “It’s the fact that all these increasing extreme-weather variables are tending to occur within a short space of time and garden plants can’t cope,” said authors Sally Morgan and Kim Stoddart. And plants that are stressed are more vulnerable to pests and diseases.

So how should we manage our landscapes as abnormal weather becomes more common?

Summer heat and drought 

What to do now

To deal with a changing climate in the short term, pay close attention to watering.

Water anything recently planted. Anything planted within the last few years will need regular, frequent watering to develop strong, deep roots.

Water everything occasionally, even drought-tolerant plants. Everything in the landscape—trees, shrubs, perennials, grasses, vines—needs occasional water to survive summers that are hotter and drier. Even plants labeled as “drought-tolerant” may not make it through the summer without some additional water.

Water your trees. In the last few years we have seen increasing signs of drought stress in our clients’ landscapes, and especially in their trees. Unlike smaller landscape plants, the signs of drought stress in trees may take a few years to appear in trees. Lack of water may eventually kill them. Read our blog post about watering trees.

Water deeply and less often, rather than watering a little bit every day. This encourages plants to grow deep roots that will make them more resilient.

Water when it’s cool to reduce evaporation. Morning is best; early evening is second best. Keep in mind that watering in the evening may promote some diseases.

Mulch to help plants retain water. A thick layer of mulch in landscape beds and around trees keeps the soil cool and reduces plants’ water needs. “Our research has shown that mulch can reduce summer soil temperatures by 20°F,” said Bert Cregg in Fine Gardening. Mulch has other benefits for your landscape: it also feeds the soil and greatly reduces weeds. Read our blog post on how to use mulch in your yard.

Water your lawn during the entire growing season. Do not allow your lawn to go dormant in the summer. It will become weak and thin, making it vulnerable to invasions from weeds, moss and insect pests. Read our blog post about lawn watering for a healthy, Bee Friendly Lawn.

Get resources and tips for smart watering. Read our blog post on lawn and landscape watering tips, with links to watering resources. And check out our YouTube playlist on Watering Your Lawn and Garden.

Plan for a future of “abnormal” weather 

Choose plants that are more resilient and drought-hardy. Consider the likelihood of “abnormal” weather when you shop for new plants.  Read our recent blog post, Choose plants for hotter, drier summers, for lists of drought-tolerant plants and tips to help them survive.

Think about your planting design. Taller plants will provide shade over smaller plants that may be more vulnerable to wilting in direct sunlight. Trees can help shade the house, keeping it cooler.

Winter rain, cold and snow

Reduce rain impact

In winter the changing climate is bringing heavy winter rains. Now is the time to look for ways to slow down water and reduce flooding, both to reduce potential damage to your yard and to protect nearby waterways.

Here are great options to reduce runoff and manage excess water.

• Use thick layers of organic mulch, such as arborist chips, bark mixed with compost or fallen leaves. Read our blog post on how to use mulch in your yard.
• Install permeable pathways that allow water to soak into the ground. Read about the pros and cons of permeable pavement.
• Install a rain garden. This is a depression created in your landscape to allow rainwater from your roof or driveway to slowly soak into the ground. You may be eligible for rebates if you install a rain garden. The City of Seattle and King County offer rebates, and there may be other rebates available. Check with your local stormwater utility.
• Use raised beds to cope with too much water. Many people are using raised beds to grow vegetables and perennials.

Prepare for winter

Trim back tall plants in fall to reduce their weight and make them less vulnerable to winter weather.

But don’t prune everything back. “Old foliage can provide a degree of protection for the crown of a plant and help it weather a cold snap,” said The Climate Change Garden. It can also provide winter habitat for wildlife and beneficial insects.

Apply mulch in fall. That’s one of the best ways to protect plants from winter damage. It will help to insulate the roots of your plants and conserve water by keeping your plants hydrated, said the Garden Hotline in Getting Ahead of Winter. Fallen leaves and arborist chips are great choices.

Plan for the future 

Select new plants with hardiness suitable for colder, wetter winters. Consider the plants’ hardiness ratings or ask your local nursery for recommendations for cold-hardy plants.

Site your new plants carefully. For example, broadleaf evergreens need protection from both winter wind and sun. These include daphne, camellia, azalea and rhododendron. Plant tall trees far from utility lines and protect them with a thick layer of mulch.

Avoid planting in areas that will stay wet in winter or that will be in the path of falling snow or ice.

Don’t plant under the eaves of your house unless you plan to water through the winter.

We can help

We can help you adapt your landscape to a changing climate. Contact us for assistance with designing and installing a sustainable landscape. And our natural lawn, tree and shrub care services will help make your valued plants more resilient against our new summer and winter climate extremes.