Alerts and Advisories as of: September 16, 2021
There are no fire restrictions at this time.
Japanese Stiltgrass, a shade-tolerant invasive annual grass of forests, wetlands, damp fields, lawns, trails and roadside ditches has been identified in Short Hills Provincial Park
Please refer to the Canadian Food Inspection Agency (CFIA) website and park kiosks for additional information and pictures.
Why it’s a problem
Japanese stiltgrass can form dense stands that outcompete native vegetation. It reduces the regeneration of native woody species and the overall biodiversity of the invaded ecosystem.
What it looks like
Japanese stiltgrass is a sprawling grass. Stems are 40-120 cm long and 1-1.5 mm thick. The lower portion of the plant is prostrate while the upper portions and flowering branches are erect. It roots at its stem nodes. Leaf blades are pale green, narrowly elliptic, 4–9 cm long and 5–15 mm wide, with a characteristic shiny midrib. Leaf sheaths are shorter than internodes. Inflorescences are terminal racemes, 3-9 cm in length.
Where it’s found
Native to Asia, this species has naturalized in the eastern U.S. and continues to spread in the northeast. One small population of Japanese stiltgrass has been confirmed and is under official control in southern Ontario.
How it spreads
Fruits and seeds are dispersed by water and can attach to clothing or animal fur. Bird seed, soil, nursery stock, hay, muddy tires, equipment, vehicles, and footwear are additional means of dispersal. Seeds can persist in the soil for as long as five years.
Japanese stiltgrass is regulated as a pest in Canada under the Plant Protection Act. The species is prohibited and therefore importation and domestic movement of regulated plants and their propagative parts is not permitted. If found, regulatory action can be taken.
Japanese stiltgrass is similar to the North American native white cutgrass (Leersia virginica). However, distinctive traits of Japanese stiltgrass include hairless nodes, smaller leaf blades, purple fall colouration, and a shinier blade midrib. Moreover, Japanese stiltgrass is an annual weed with fibrous roots and a spike-like inflorescence, whereas Leersia species have rhizomes and a panicle type of inflorescence. Japanese stiltgrass may also be mistaken for another North American native, deertongue panicgrass (Dichanthelium clandestinum), as well as for small carpetgrass (Arthraxon hispidus).
What to do about it
Please contact your local CFIA office if you think you have found Japanese stiltgrass or other regulated invasive plants. The CFIA will follow-up to determine if further action is needed.
*Invasive plants are plant species that can be harmful when introduced into new areas. These species can invade agricultural and natural areas, causing serious damage to Canada's economy and environment. To find out more, visit www.inspection.gc.ca/invasive or contact CFIA’s Invasive Alien Species and Domestic Programs section at email@example.com. To find your area or regional CFIA office, visit http://www.inspection.gc.ca/about-the-cfia/offices/eng/1313255382836/1313256130232