Climate change and horticulture

Garden Clippings for August 13, 2022

The past few years of weather have been a roller-coaster ride and climatologists are saying it is only going to get worse.  Europe’s current heat wave is relentless.  Here in Lambton County June and July rain was extremely sparse and the deluge came down on August 3, 4, and 5.

For Canadians the recent weather extremes are a wake-up-call.  Forest fires, floods, drought and melting glaciers are now commonplace.  And unless we find a way to make climate change do a rapid three-sixty, weather extremes are here to stay.

In the few years that I’ve been involved in all things gardening, I’ve seen that winters have become milder, making it possible to grow plants that would struggle to survive just a few decades ago.  Marginally hardy plants such as Japanese Maples, Rhododendrons, Redbud and Butterfly Bush would have struggled in the 70’s and 80’s but now grow with ease throughout Southwestern Ontario.

But that’s where the good news ends.

Invasive, non-native plants are taking advantage of milder winters and earlier springs and are growing more aggressively than ever before.  We continue to add plants to the invasive species list.  Of particular concern is Garlic Mustard, Purple Loosestrife, and Phragmites.

In my own backyard, we are endeavoring to pull out Knapweed, an invasive weed that is slowly devouring the grassland.  The Knapweed is not particularly ugly, but its benefit to the environment is questionable, while grasses and native species are home to plenty birds, rodents and insects.

The changing precipitation patterns along with higher temperatures are triggering plants and flowers to grow earlier than normal.  That’s not a big problem for you and me in our backyard gardens but may disrupt the timing for birds, insects and animals who rely on critical timelines for feeding and breeding.

At a time when we are increasing our awareness and appreciation for pollinators, birds, and other wildlife, we are seeing climate change threaten their livelihood because flowers bloom earlier or later than their formerly predictable dates.

Keen gardeners are also keen to respect the environment.  We are doing our part by driving cars with lower emissions, taking our bikes to run errands, reducing our use of single use plastics, and switching light bulbs to improved energy efficiency.

In the garden, we can do more to show kindness to the environment.  We can cut the lawn less often, gather rainfall in barrels and leave the leaf blower in the garage.  We can also reduce water consumption by allowing grass to suffer during dry spells.

Wise gardeners also know that mulching is good for plant growth and helps retain soil moisture.  Mulch reduces temperature fluctuations in soil, keeps weeds at bay and improves soil nutrient levels.

Horticulturists and nursery growers are increasing the numbers of native plants in their production farms.  Garden centres and municipalities are taking the lead by offering more native trees, shrubs and native perennials because they are often proven to be hardier and able to withstand weather fluctuations.

Perhaps the most impactful action home gardeners can take is the planting of trees.  As time has gone on, we have significantly reduced our tree coverage in order to make way for parking lots, roadways, football fields and buildings.  Trees are nature’s air conditioners, nature’s air purifiers and are home to countless insects, birds and other animals.