Friday, February 24, 2017

Soil Health, Invasive Species and Your Pollinator Garden.

March is around the corner! It’s time to step up plans for that pollinator garden you’ve been dreaming about all winter. One of the most important things to think about is preparing your site for planting. “Soil is the most important aspect that we routinely overlook,” says Kellie Sherman, Coordinator at the Ontario Invasive Plant Council. “A first step is ensuring that the soil is healthy."
Kellie recommends looking for health indicators such as nitrogen, phosphate and potassium. Is the soil sandy or clay-based? What is the water drainage like? She suggests researching the soil type for your area. As this can be daunting, Kellie suggests getting your soil tested. You can pick up a kit from places like Home Depot and then find further research online about results.

Recognizing Invasive Plants.
Periwinkle (Invasive groundcover).
Another critical point of concern are invasive plants such as multiflora rosa, periwinkle ground-cover, Himalayan balsam and jewelweed. Purple loosestrife and honeysuckles are a problem too. But why are invasive species so harmful?

According to Kellie, invasive species are the second most cause of extinction after habitat loss. Invasive species impact the environment and the economy and have an effect on society. “Invasives are aggressive.They compete with species that help our economy and they carry potential diseases that spoil our crops,”she says. Environmentally, invasive plants can have a large impact on natural areas and threaten the important services to both wildlife and humans that they provide. Invasives can overtake forest understorey and prevent forests from regenerating so that we won’t see new trees come up. Kellie points to the Norway maple as being a prolific seed producer invasive in the Toronto Ravine for example. “Research is showing that it significantly reducing pollinators in the area, oaks and maples are not growing.” Invasive plants can change the composition of soil.

As well, there is no good evidence that invasives provide food for pollinators. “Invasive plants can affect forage quantity, reducing biodiversity,” says Kellie. By contrast, “native plants have evolved over eons to work with biodiversity, so they are a better food source for pollinators.”
Society-wise, invasive plants like the giant hogweed can cause irritation to skin.

“Even in a green bin, invasives such as periwinkle can spread,” Kellie warns. She suggests that with something like buckthorn, you could cut it it back before it produces berries, then let the branches decompose. You can check out common invasive plants on the Grow Me Instead Guide, an invaluable guide that helps you identify invasive garden plants and provides suitable native or non-native, non-invasive alternatives.