It looks attractive, but once it gets into your garden, it never leaves. It will take over your yard, your house, your neighbourhood, growing up through asphalt and even penetrating concrete foundations of homes.
It sounds like something out of a B-grade 1950s horror flick, but the knotweed threat is real. And it鈥檚 an example of the harm that can happen when we introduce species where they don鈥檛 belong.
Like most invasive species, knotweed has spread outside its original East Asian habitat because people found it attractive and easy to grow. It was introduced into North America in the 1800s as an ornamental plant, to control erosion and as fodder for livestock. It is found in six provinces and 39 states.
It is a major problem in Great Britain, New Zealand, Australia and Tasmania. The World Conservation Union lists it as one of the world鈥檚 worst invasive species. When it gets established, it eliminates all other plants in its territory. That causes economic losses, as well as destroying natural habitat.
The Capital Region Invasive Species Partnership wants to ensure nasty knotweed doesn鈥檛 take over the Island. People who suspect they have the plant are asked to report it to the Coastal Invasive Species Committee, which is part of the capital region partnership, by calling 250-857-2472 or emailing [email protected].
It鈥檚 an impressive plant with bamboo-like stems, arching branches and spear-shaped green leaves of up to 12 centimetres. Its flowers appear as creamy white clusters at the tips of the stems in late summer.
And just in case it has sneaked in under an assumed name, you should know it is also called fleeceflower, Himalayan fleece vine, monkeyweed, monkey fungus, Hancock鈥檚 curse, elephant ears, pea shooters, donkey rhubarb (although it is not a rhubarb), sally rhubarb, Japanese bamboo, American bamboo and Mexican bamboo (although it is not a bamboo).
While knotweed is not as big a problem on the Island as it is in the U.K., it鈥檚 important to find out where it is and to eradicate it as soon as possible.
Cutting it down or digging it up won鈥檛 do the trick 鈥� tiny pieces of the plant left in the soil, tossed in the compost or allowed to drift down a stream will sprout and begin a new colony. The partnership is providing a free service this summer in which professionals inject herbicide into the stem of the plant.
鈥淭here鈥檚 a cost to doing nothing,鈥� says Rachelle McElroy, executive director of the Coastal Invasive Species Committee. 鈥淚f we don鈥檛 know it鈥檚 there, by the time we become aware of it, it鈥檚 too late.鈥�
While many nurseries and garden centres are aware of the problems with invasive species, sa国际传媒 has no law against selling such plants. Perhaps that should change.
鈥淲e don鈥檛 want it to become like Scotch broom,鈥� McElroy said, referring to the yellow-blossomed shrub that has infested thousands of hectares on the Island, damaging native ecosystems.
Broom was brought to the Island in the mid-1800s and encouraged by settlers who wanted to 鈥淓uropeanize鈥� the landscape. Gardening and landscaping are integral to the Island quality of life, but there鈥檚 a lesson from broom and knotweed 鈥� be careful what you plant. We enjoy many flowers, shrubs, trees and vegetables that are not native to this region, and they enrich our lives, but we should be on guard for those plants that spread too easily and have no natural enemies.
Nature鈥檚 a lavish spender here, but our ideal growing conditions mean aggressive foreign plants can too easily harm our island paradise. We need to be vigilant.
With apologies to a 1970s margarine commercial:
鈥淚t鈥檚 not nice to fool with Mother Nature.鈥�
