Dandelions in the lawns are just fine, but St. Albert gardeners could be asked to remove from their yards some old favourite plants that have been found to be invasive alien species that clog the waterways and natural parklands of Alberta.
“The Weed Act of 2010 added several new plants to the invasive plants list. They have added plants that have more ecological problems than environmental problems,” said Kevin Veenstra, pest control foreman for the City of St. Albert.
The City of St. Albert’s weed control budget is $35,000 and most of that is directly related to controlling invasive alien species that are not native to Alberta. Those pesky, grow-anywhere dandelions, which are bright and sunny and glorious at this time of year, are aliens but are no longer on the Alberta invasive species list.
“It was a surprise that dandelions were taken off the weed list but I think they removed them because they are so widespread that they can be found everywhere in Alberta. There is no hope of eradicating them and trying to eliminate them for cosmetic reasons was contributing to increased use of pesticides,” Veenstra said.
So if you leave the dandelions, the bylaw officers will not care, because for the most part the city does nothing to eradicate dandelions in its own fields and parks.
On the other hand, if your garden contains old favourites such as oxeye daisy, Himalayan impatiens or creeping bellflower, you could be asked to remove them from your property.
The list is divided into two parts. The most invasive species are labelled ‘prohibited noxious.’ Those still deemed undesirable but less invasive are labelled as ‘noxious.’
Some noxious species are Canada thistle, creeping bellflower and oxeye daisy.
“Noxious means you are required to control them from going to seed but those that are on the prohibited noxious list have to be killed,” Veenstra said.
The 41 species listed as prohibited noxious include flowering rush, Himalayan balsam, which is also called poorman’s orchid or Himalayan impatiens, purple loosestrife and tansy ragwort.
For many home gardeners, finding their favourites listed as noxious may be hard to understand because they may have purchased them at a garden centre or they may have been a gift from a family member or friend.
To get rid of noxious or invasive species, put them in a plastic bag and dispose of them in the brown bins along with wastes that go directly to the landfill to be buried. Do not chance putting these plants in the green bins because the seeds and the plant parts such as a piece of root may not always be killed by composting.
Be careful of seed packets that are labelled as wildflowers. Many of these are not locally packaged and may contain invasive species among them.
For more information and for a complete list of invasive plants, visit www.invasiveplants.ab.ca
Favourite baddies
• Purple loosestrife is sometimes referred to as the beautiful killer. It has strong purple spikes that look striking in any garden. However, each mature plant produces up to 2.5 million seeds and even ornamental cultivars that were originally thought to be sterile have been shown to cross-pollinate and produce seeds. Purple loosestrife clogs waterways, ponds and rivers. In St. Albert it has been systematically pulled for nearly 20 years so that now there are just five patches remaining.
• Creeping bellflower, commonly referred to as bluebells by many gardeners, reproduces by seeds, creeping rhizomes and tuberous root pieces. It is well loved by gardeners because it is so drought tolerant and for the same reason, it is hard to kill. It is resistant to herbicides and one plant may produce 15,000 seeds.
• Yellow clematis is in many St. Albert gardens because the vine is hardy and makes a great screen cover. The long silky tufted seeds blow on the wind and aggressively take over, replacing native plants.
• Himalayan balsam is a plant that is easily grown and often shared among gardeners because it grows four or five feet high and its pink blooms are impressive. The orchid-shaped flowers resemble a British policeman’s helmet but the seed capsules explode upon contact and catapult seeds six metres or more.
• Flowering rush is a plant favoured by gardeners with ponds. It is now growing in the Sturgeon River and is very difficult to eradicate.
“Flowering rush is beautiful when it blooms because it has these big spikes with umbrella-shaped pink flowers. We have 200 plants in St. Albert now and the only way to get rid of it is to cut the plants before they bloom. If left alone, eventually, they could choke the river,” Veenstra warned.
• Oxeye daisy may be one that was purchased from a nursery because for many years it was not on the noxious list. It has multiple unbranched stems that produce the traditional white daisy flowers and the blossom petals have a slight notch at the top. Oxeye daisy is similar to scentless chamomile that has been on the noxious list for many years. Both daisies can produce thousands of seeds. They also grow from root pieces and when they escape the garden, they become a huge problem in farmers’ fields. Shasta daisy is a cultivar of oxeye and was originally sterile but can revert back to being fertile. The two plants can crossbreed, resulting in an invasive hybrid. There are no native white daisies in Alberta.
