Invasive Plants

Noxious Weeds in Grasslands Everywhere

These are more than just weeds – they are a menace.

Due to the fact that the insects that predate them, animals that browse on them, and conditions that limit their growth are not present, they can grow unchecked.

Kudzu is a perfect example of what can happen when some well meaning person brings an exotic non-native plant with all the best of intentions to a new area. The heat and humidity of some of the areas that Kudzu was planted gave it turbo charged growth which can reach as much as a meter a day! Whole houses, cars and bridges have disappeared under the rampant vine.

Luckily, kudzu won’t grow in cold climates such as Canada, but there are other plants that have been brought here either on purpose as a well meaning addition to the forage crops for cattle or other livestock, or as a garden ornamental.

Some that become invasive in a new land are sweet clover, purple loosestrife and Iris pseudacorus.

One weed brought in accidentally is plantain which was given the name White Mans Footprint by First Nations people for its habit of following along behind the progress of the pioneers across the prairies.

It grows best in packed poor soil, provided by the heavy wagon traffic pulled by oxen or mules.

Other invasive plants that choke out wild and native plants or other less aggressive and desirable forage plants such as timothy grass and alfalfa are knapweed, hoary alyssum and ox-eye daisy. All these invasive plants were brought in and are now spread around by the purchase and feeding of infested hay from other areas.

Knapweed is also spread by getting caught underneath a vehicle on range land to be dropped along highways and other areas. In some cases, they can be a valuable source of nectar and pollen for beneficial insects, but the disadvantages far outweigh the benefits of most invasive plants.

In an ironic twist, some insects such as certain weevils usually considered as pests in gardens, have been specially bred to predate invasive plants.

Gypsophila, a lovely ornamental plant known as babies’ breath and used extensively in bridal bouquets by florists is now loose in the Boundary Kootenay region. It loves dry conditions, and when the August winds start to blow, the whole area is filled with tumbleweeds spreading their seeds around everywhere.

Many invasive plants use drought smart strategies to survive.

This makes it particularly difficult to eradicate them, as they are prolific self seeders hitchhiking their way into areas that get few visitors. The old saying, one years seeding means seven years weeding is never truer than with invasive plants. It's essential to pull plants just before they set seed, and burn or otherwise get rid of them completely - never compost them, or the seeds are all through your garden too.

Please think carefully before installing the latest unproven plant in your garden, in case it’s an invasive plant that will threaten sensitive wildlife habitat.

go to Drought Smart Plants home page

Sustainable Gardening

Weeds