Invasive Plants

Help keep them out of Cypress Park!

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Cypress Provincial Park is valued for its easily accessible natural environment and its great variety of native plants, but in recent years invasive plants have become a concern in some areas of Cypress Bowl and Hollyburn Ridge.  These plants pose a serious threat to the park’s natural environment; one (Giant Hogweed) is also a threat to human health.

Described below are three invasive plant species of particular concern at Cypress.  General information about invasive plants and how to report sightings to authorities can be found here. Lists of invasive plants now found in the park can be found here. By learning how to identify and report invasive plants, we can all help to keep them from encroaching on the park’s treasured natural environment.

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Young Japanese Knotweed plant – Black Mountain ski slope, August 2011

Dick Beard photo

Japanese Knotweed (Fallopia japonica): Knotweed is considered one of the most serious invasive plants worldwide due to its ability to spread quickly and form dense thickets, crowding out native plants and reducing food sources for wildlife.  It is able to establish itself from tiny root fragments and can push through asphalt, creating serious structural problems.

In Summer 2010, Japanese knotweed was found on Cypress ski slopes; this infestation has been attributed to work done in preparation for the February 2010 Winter Olympics.  In order to control knotweed and other invasives found in the Olympics venue area, BC Parks obtained five years of secure funding for invasive plants inventory/monitoring work through an agreement with VANOC (Vancouver Olympics Operating Committee). Knotweed found in 2010 was removed manually.

In 2011 Genoa Environmental undertook a comprehensive invasive plants inventory of Olympic venue areas. Thirteen plant species of concern, including Japanese knotweed, were noted with recommendations for treatment. Knotweed was treated chemically. Genoa Environmental reported: “the moist soils, streamsides and wet meadows found at Cypress Bowl are all highly susceptible to invasion [by Japanese knotweed].” Inventory/monitoring work will continue in 2012 and beyond, if needed.

Young Giant Hogweed plants – Cypress Bowl Road ditch below Hollyburn Ridge area, August 2010 – Katharine Steig photo

Giant Hogweed (Heracleum mantegazzianum): Giant hogweed was discovered a few years ago in a ditch on the Cypress Bowl Road just below the Hollyburn Ridge power lines. It was also found in the Nordic ski area across the road from the tubing area. The leaves and stems of this plant contain a highly toxic sap that can cause serious skin irritation, burns and even blindness.

Although BC Parks staff had worked to remove the plants from these areas, the colony increased greatly during the cool, wet spring of 2011, becoming the third largest infestation (over half a hectare) found in Metro Vancouver. In Summer 2011 an Invasive Plant Council of Metro Vancouver team treated the plants with herbicide. A site visit in November showed that the treatment had been effective and that native grasses and shrubs had moved back into the treatment area. However, continued monitoring will be required to ensure eradication of this dangerous invasive plant. 

Scotch Broom – 4th switchback on Cypress Bowl Road, July 2010 – Katharine Steig photo

Scotch Broom (Cytisus scoparius): Although small colonies of Scotch broom have been present for several years on some Cypress Bowl ski slopes and on the Cypress Bowl Road, they appear to be increasing.  A large infestation was discovered in Fall 2011 on Black Mountain’s First Sun and Panorama ski runs.  Scotch broom crowds out native plants and changes the composition of the soil. It also burns easily and can be a fire hazard.  New efforts will be required to keep it under control.