DON'T GROW THERE, GIRLFRIEND!
Watch out for these noxious weeds
Living in a Zone 3b creates myriad challenges for garden nuts. With a very short growing season, chinooks, hail, and the winds that seem to come up from nowhere, gardeners can be forgiven for embracing anything that grows well.
Not so fast. There is a very lengthy list of prohibited noxious weeds as stated in the Province of Alberta Weed Control Act and some of the brutes listed may surprise you. Everything from autumn olive and thistle to common St. John’s wort and Medusahead are listed in the publication along side no fewer than nine species of knapweed.
All are illegal and therefore must be destroyed.
Calgarians will remember a time when our river banks were covered in prohibited noxious purple loosestrife — a rather pretty plant that arrived in eastern North America in the early 1800s. Purple loosestrife is one nasty weed and once it gets a foothold, look out. An estimated 190,000 hectares of wetlands, marshes, pastures and riparian meadows are aff ected in North America each year, with an economic impact of millions of dollars. But thanks to the tireless eff orts of the City of Calgary Parks Department, our riverbanks are now 99 per cent loosestrife free.
Next on the list of plant thugs are those considered noxious — or obnoxious as some might say. Again, you may be surprised as to those making the cut. Common baby’s breath? Tall buttercup? Yellow clematis? Even the Shasta daisy can convert and hybridize with the ox- eye daisy — a noxious weed. No surprise that creeping bellfl ower is mentioned as this baby is nigh impossible to get rid of once it establishes itself in borders and beds. And who knew that all species of brome are noxious? And here I thought it looked so pretty covering ditches and hills on the Coast with its happy yellow stalks. But then there are probably those who think dandelions are pretty.
Next on the nasty list are those plants considered invasive. Sure, they are not prohibited noxious weeds or even ( ob) noxious, but if left uncontrolled, they will aggressively spread and eventually take over the entire garden. Goutweed gets top marks for being invasive. Sometimes known as bishop’s weed or snowonthe- mountain, this ground cover will live anywhere- even under spruce trees ( to a degree). Controlling this spreader in an environmentally friendly way is as simple as placing layers of newspaper- wetted down so as not to blow away- and top dressed with a few centimetres of soil. In about a year’s time, gonzo is the goutweed and the soil will be surprisingly fertile. There’s that method and then you can always either Agent Orange the heck out of goutweed or spray liberally with Roundup — but neither are readily available on the market and are environmentally hateful.
Others members in the “don’t grow there girlfriend” club include caragana or Siberian peashrub and Norway maple. The former will easily choke out fl owering shrubs and is not songbird friendly. The latter — Norway maples — are not to be confused with sugar maples, which are native to North America. The Norway maple can be distinguished from other maple trees because the leaves and twigs ooze milky sap when cut. Norway maples also prevent anything from growing under their leaf canopy because they are so adept at absorbing water and nutrients.
Make sure to check your garden for prohibited noxious and noxious weeds and destroy them as soon as possible.
It’s up to you if you choose to leave invasive plants alone but your neighbours might not be too happy if you do.