The trees are leafing out, flowers are blooming and the weeds are thriving.
Plants are not weeds when they are in their natural habitat. They only become weeds when they are introduced into a new environments and are hard to control. Weeds, to most people, are any plant that is growing where it isn’t wanted. This means that certain plants that are considered weeds by some people and not others. To be weedy, a plant must possess the ability to spread quickly through roots, seeds or both.
Underground rhizomes are thin roots that grow quickly under the soil producing a new plant a distance from the original. It isn’t until the plant’s growth penetrates the surface that the plant’s spread is detected. It is hard to eradicate plants that spread quickly by underground rhizomes as every piece of root must be removed or the plant can, and will regrow.
Seeds are a quick way to produce a massive amount of new plants. Weedy plants often produce a large number of seeds that are spread by wind, animals and birds. The seeds that land in cultivated areas such as a flower garden are a nuisance but easily removed at the seedling stage. In cultivated land there are a number of options which include hand pulling, chemicals or mechanical cultivation.
Plants that germinate in a pasture, roadsides or native grassland are harder to remove. These areas are not checked for weeds on a regular basis which means the plants can become established before they are discovered. It is labour intensive to pull or dig large areas of the weeds, while mechanical cultivation would disturb the surrounding vegetation. Often the use of chemicals is the only option.
Aggressive rooted plants can live and look great in gardens as long as they are carefully placed. They need to be used in a large area by themselves; one where they are confined by cement, constant mowing or cultivation. Do not give aggressive rooted plants ideal growing conditions. Place them in shady areas of poor soil allowing them to fill in where other plants will not survive.
Deadheading — removing spent blooms — removes the risk of plants reseeding. The time spent at this task is shorter than the time spent removing the seedling at a later date.
The Alberta government has legislation in place to deal with weeds, classifying them as either restricted, noxious or nuisance.
Restricted weeds are ones that only occur in a few locations in Alberta, but if left unchecked would spread through out the province. It is believed that if these plants are recognized and eliminated by means of cultivation, removal and chemicals, the plants will not spread to other areas. At this stage it is possible to eliminate the weeds.
The list of noxious weeds is over three times as long as restricted ones. Noxious weeds have become established in many different parts of the province taking over from native species. As the plants are too established to be eliminated they are to be controlled. Once again the use of removal, cultivation and chemicals are encouraged. If left unchecked, these plants will spread to adjoining areas and become more of a problem.
Nuisance weeds are ones that are found throughout Alberta. These are the familiar ones that grow in waste areas and are pulled from your garden. While they are responsible for loss of yields in many crops, they are too well established to ever be eliminated.
All weeds are opportunist. They grow where they land as long as the soil conditions and climate are suitable. For this reason plants that are a problem in one area might not be in another. Municipalities have the ability to upgrade weeds from nuisance or noxious status.
This is also why some plants that are listed as noxious are never seen in your area.
It is important for a gardener to know their plants and how they multiply to ensure that aggressive plants are kept in check.
Linda Tomlinson is a horticulturalist and educator living in Rocky Mountain House. You can contact her at firstname.lastname@example.org.