How should we manage our landscapes as “abnormal” weather becomes normal?
The climate is changing, with “normal” weather proving more elusive. This affects how we approach our landscapes.
“Aberrant temperatures with searing heat and extended drought, or heavy wind and rain, crippling snowstorms and treacherous ice might just be our new normal,” said Lorene Edwards Forkner in a recent article in The Seattle Times.
Forkner reports that in 2021 we had a cold, wet winter, characteristic of a La Niña weather pattern. A chilly spring was followed by record-breaking high temperatures and very little precipitation in summer.
In 2022 we had another cold and wet La Niña winter, followed by another record-breaking hot and dry summer. We only received 0.5 inch of rain last summer, far below the average of 3 inches. After a warm and dry autumn, last winter was a rare third consecutive La Niña weather pattern. We saw cold and wet conditions, including an “epic ice storm” in December.
This year, after a chilly spring, May saw a “bizarre heat wave that punished spring gardens with temperatures approaching 90 degrees,” Forkner wrote. And now it is hot and dry again. The state climatologist predicts above normal temperatures and below normal precipitation for the rest of the summer.
According to The Climate Change Garden, the problem is not just that overall climate patterns are changing. “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
In the short term, pay close attention to watering. Anything planted within the last few years will need regular, frequent watering so it can establish strong, deep roots.
Everything else in the landscape—trees, shrubs, perennials, grasses, vines—needs occasional water to survive summers that are hotter and drier than the old “normal.” Even plants labeled as “drought-tolerant” may not make it through the summer without some additional water.
As hot and dry summers have become the pattern, we see increasing signs of drought stress in our clients’ landscapes. We are particularly concerned about trees. Unlike smaller landscape plants, the effects of drought stress may take a few years to appear in trees. Lack of water may eventually kill the tree. Read our blog post about watering trees.
Rather than watering a little bit every day, it is much better to water deeply and less often. This encourages plants to grow deep roots that will improve their resilience in future years.
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 will 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.
Your lawn needs water 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.
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
In the long term, consider the likelihood of “abnormal” weather and choose plants that are more resilient and drought-hardy. Check out the lists of drought-tolerant plants in Great Plant Picks. You can find more plant lists in our blog post on drought-tolerant plants.
Think about your planting design too. 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
Rain
Heavy winter rains may be part of the new weather pattern. 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.
Three great options to reduce runoff:
- Thick layers of mulch, such as arborist chips, bark mixed with compost or fallen leaves. Read our blog post on how to use mulch in your yard.
- Permeable pathways allow water to soak into the ground. Read about the pros and cons of permeable pavement.
- Rain gardens. A rain garden 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, King County and Snohomish Conservation District all offer rebates, and there may be other rebates available. Check with your local stormwater utility.
Raised beds are a way to cope with too much water. Many people are using raised beds to grow vegetables and perennials.
Preparing for winter
Trim back taller 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.
We may sound like a broken record, but mulch helps here too. A fall application of mulch is one of the best ways to protect plants from winter damage. “Adding a few inches of a good organic material to the soil surface 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 a future of “abnormal” weather
Colder, wetter winters, with occasional extreme weather events such as cold snaps and heavy snow, may no longer be abnormal weather. Take that into account when selecting new plants for your garden. Consider their hardiness rating or ask your local nursery for recommendations for cold-hardy plants.
Take care to site your new plants well. “Site broadleaf evergreens that easily succumb to winter damage in areas where they are protected from both winter wind and sun. These include daphne, camellia, azalea and rhododendron,” said the Garden Hotline. And plant tall trees far from utility lines. Make sure any new plantings have a thick layer of mulch to protect them from cold and prevent them from drying out.
Don’t plant in areas that will stay wet in winter or that will be in the path of falling snow or ice, said the Garden Hotline. And don’t plant under the eaves of your house unless you plan to water through the winter.
