The Earth is losing species every day because of alien invaders. The word alien as used here refers to non-native species. A plant that originated in Asia and which now grows in alien og seeds Europe and in North America is said to be a native of Asia and an alien to its new growing regions.
Plants have been following behind people on the move for a very long time. Seeds have ingenious ways of hitching a ride on people’s clothing and on animal coats. Contaminants come along with plants that are purposefully moved with people. Coming to a new land people would bring plant starts or seeds of favorite foods and maybe even soil from back home. Animals and water fowl transport many plants during their lifetimes.
However they get here, certain alien plants have become pests to contend with. Kudzu vines choke the daylight from trees along the highway, phragmites reeds choke out native plants at the edge of the lake, Tear-thumb or Mile-a-minute vines grow over and choke out anything in their path, purple loosestrife has replaced many wetland native species, and the list goes on. Attempting to control the massive plant overgrowth has cost many hours labor for very little in results.
In the gardening world there are many garden escapees that have naturalized to become part of the landscape. Eradication efforts may prove futile as one thing the aliens have going for them is that they don’t have many predators, if any. This means no natural means of growth control, so people have to put in the effort.
Invasive weeds are just that, invasive. Where a new plant takes root and finds little competition it is likely to survive and produce offspring. It’s kind of like survival of the fittest. The better that the new plant’s offspring can compete with native plants, the more invasive it is. When alien plants compete so well that they displace native species, the alarm bells should go off because that means the native plants may become endangered.
We, as gardeners, owe it to ourselves to be part of the solution not part of the problem. We can garden with native plants and have lots of success. Native plants are naturally adapted to the region and soil types that are present. They won’t need lots of extra attention, like constant watering, because they’re already adapted to the local conditions.
Tropical plants that should be living in a jungle somewhere would need a lot of extra watering compared to a native plant. A perfect example is a moisture-loving plant called Elephant’s Ear (Colocasia sp.) which is native to tropical Asia. The best place for it in a North American garden would be in a water garden so it could get the moisture it requires for best growth. Since it won’t overwinter north of zone 6, northern gardeners must dig up the bulbs or tubers and store them for the next growing season. Elephant’s Ear growing in a temperate garden won’t reach its full stature unless it is artificially maintained with a soaker hose. Why not be a little more kind to the environment and plant a native grass instead?
One important function that we collectively serve when we choose to garden with native plants is that we are actually establishing a sort of refuge for these native plants. A refuge from which seeds or root stock can be taken to further reproduce the native plant is a garden worth tending.