By Chad Ingram
“It’s not as simple as saying native plants will do better in climate change” says Belinda Gallagher.
Gallagher a county resident botanist Echo columnist and former head of horticulture at Burlington’s Royal Botanical Gardens is speaking at the U-Links Centre for Community-Based Research’s annual Celebration of Research at Haliburton’s Fleming College campus.
She’s talking about the significant impact climate change will have on Haliburton County’s plants ecology and ecosystem.
Gallagher tells the room there are three factors one must understand.
One is that temperatures are changing and the area is seeing fewer snow-covered and frosty days. More warm spells like the one the area experienced in early March can be followed by sudden cold snaps more severe than in the past.
The second is that the county along with the rest of the planet is experiencing more extreme weather conditions.
“We’ve had extreme conditions in the past but our extreme events are becoming more frequent” Gallagher says adding that a point has come where historical weather data can basically no longer be relied upon.
The third factor is an increase in greenhouse gases in the atmosphere as a result of both manmade and natural factors.
“When we combine those three factors then we can talk plants” Gallagher says.
Warming temperatures pose a number of risks to plants. One is that a longer warm season gives pests more time to reproduce.
As Gallagher points out warmer temperatures are not just a liability during summer but during winter months as well.
For example four consecutive days of temperatures at minus 22C each year helps to mitigate the gypsy moth population.
“Gypsy moths are loving the fact we don’t have as many cold days” Gallagher says.
Apple trees need a chilly period throughout the winter to bloom properly. The same goes for peonies.
“Plants are just not getting that trigger to go dormant” Gallagher says adding that while some plants shift their bloom times others don’t seem to be able to.
During increasing warm spells in late winter and early spring some plants will start blooming prematurely those buds dying when a severe cold snap comes along.
“Plants get tricked into thinking it’s time to come out” Gallagher says.
At least a third of perennials in the area are at risk because they are not shifting bloom times with familiar plants such as golden rod black-eyed Susans bee-balm buttercups trilliums ladybells and teak being affected just to name a few.
Over time plant species will actually move from an area gravitating to more suitable climes.
“Plants move slowly” Gallagher says. “They can’t walk or run but they will move.”
Familiar tree species in Haliburton County – white spruce and birch for example – are heading north and over time their absence is likely to change the county’s habitat.
“The winner in this is the maple which seems to be expanding its reach in all directions” Gallagher says.
In this way Gallagher is a bit hesitant about the term “native” since a plant that may have grown in the county say 7000 years ago may not grow here now.
In fact as she points out some familiar species are actually invasive species.
“The friendly day lily . . . which isn’t a lily . . . is not a native plant never was a native plant and it is on the invasive plant list” she says.
Gallagher recommends people consult invasive plant guides before purchasing vegetation to plant on their properties adding that some species sold in annual baskets are in fact invasive.
Longer warm seasons are also giving invasive species that once would not have had a long enough growing season to seed time enough to do so.
Gallagher says grasses often used in commercial landscaping fall into this category.
Changes in greenhouse gases are allowing some species – poison ivy and many vines for example – to especially thrive.
“Plants who would normally be fine to deal with are becoming aggressive weeds” Gallagher says.
The changing climate means many gardeners are switching the flowers they plant using types that are half a zone warmer. Farmers are planting different crops ones that are more heat-resistant.
In forestry there is a controversial practice called assisted migration which entails taking tree species from a more southern area and transplanting them in a more northern area in anticipation of climate change.