Invasive species experts are asking those decorating for the holidays to check their trees, wreaths and garland for hidden pests.
Insect eggs from spongy moths and spotted lanternflies could be hiding under tree branches, while non-native plants like English holly, a staple plant in holiday arrangements, can pose risks to nature.
Experts say these invasive species have the potential to harm the local environment after decor is disposed of from people’s homes.
“Invasive species don’t rest,” said Derissa Vincentini, the community science co-ordinator at the Invasive Species Centre. “You thought the growing season was over and you don’t have to worry about them, but they could still be lurking in your holiday decor.”
Christmas trees sold at big-box stores often come from other cities, Vincentini said, potentially bringing invasive egg masses along with them.
While the egg masses, which can contain up to a thousand eggs, won’t cause any harm in homes, Vincentini said problems arise when the insects get back outside.
“Once the spring comes and it starts to thaw, those eggs will start to hatch and then they can reach their hosts in the natural environment in a new location,” she said.
Traditional holiday plants like English ivy, English holly and invasive barberry can also be harmful if they end up in London’s natural environment, according to experts.
“Eventually they’ll outcompete all of the native plants and really cause a lot of issues for the wildlife in urban wild spaces,” said Janice Gilbert, the executive director of the Invasive Phragmites Control Centre.
“Our native insects rely on our native plants for food sources, so if we’re replacing our native plants with these invasive ones, we’re reducing our insect population which reduces food for our birds,” Gilbert said.
Insects hidden in branches
Vincentini said spotting invasive insects in holiday plants is not always easy because the insects are not feeding on the greenery.
“These egg masses are going to be very dormant so you’re not likely to see any insects or any damage in regards to your Christmas tree,” she said.
“These pests are just very opportunistic when they’re laying their eggs … especially if they can find a spot that’s protected from the elements, so the underside of branches is a particularly good spot to look for these egg masses.”
Spongy moth egg masses are about the size of a thumb and tan in colour with a felt-like texture, while spotted lanternfly egg masses look like a grey-brown smear of mud, she said.
When they get back into the environment, Vincentini said spongy moth caterpillars feed on tree leaves causing defoliating forests, while spotted lanternflies tend to go after soft fruit trees and grape vines, impacting produce production.
So, if people see either egg mass in their home, Vincentini suggests they snap a picture of it to send to the Invading Species Hotline before scraping the mass off the tree with a butter knife.
Spongy moth masses should be soaked in a bucket of dish soap and water for 48 hours before being thrown out. Spotted lanternfly masses should be frozen in a baggy of hand sanitizer or rubbing alcohol then reported to the Canadian Food Inspection Agency, she said.
Let plants rot before tossing
Vincentini said plants frequently used in decor like wreaths or garland can also cause problems if not disposed of properly. If they’re already in people’s homes, she suggests people throw them in the garbage, not compost bin, at the end of the holiday season.
Gilbert added that the plants should rot before being tossed.
“The best thing to do is put it in a plastic garbage bag or brown paper waste bag and just let the plant material rot so it’s no longer viable,” she said.
Gilbert also wants to remind the public that just because they see a plant in the city, that doesn’t mean it’s native or good to use in holiday displays. She said that many people cut phragmites and silver grass, both invasive feathery grasses, which spreads their seeds around.
“Humans are great spread vectors for invasive plants and insects, and many times it’s just because of a lack of awareness,” Gilbert said.
Winterberry a native alternative
At VanLuyk Garden Centre in London’s east end, Suba Sivakumar said people can consider using safe alternatives to classic holiday plants.
“English holly is one of the stems customers use, so it has bright green leaves and red berries, but there is a very good alternative which is called winterberry holly, which is a native species,” she said.
Other native greenery that Sivakumar recommends people use in their holiday displays include white pine, cedar and red-osier dogwood branches.
“It’s always nice to follow traditions as long as people are aware of the invasive species and pest problems,” Sivakumar said. She hopes people can celebrate the holidays while helping nature stay intact.
