Spartina are invasive salt-tolerant grasses that threaten our shorelines by out-competing native marsh plants and reducing liveable habitat for wildlife. They also compromise coastal industries such as shellfish growers, tourism and fisheries. Some species of Spartina even have the ability to alter tidal patterns which can increase the risk of flooding in some areas.
Why Should You Care?
Baynes Sound is an area along the Georgia Strait that stretches from just North of Comox to just North of Qualicum Beach and includes both Denman and Hornby Island. It is also currently the only place on Vancouver Island that has Spartina (Spartina densiflora and Spartina patens). Its presence here is particularly concerning due to the high volume of coastal-based shellfish industries located within the area, as well as the world-class diving sites located along Denman and Hornby Island.
Impacts: Agricultural: Not a problem on agricultural lands. Ecological: Competes with native flora of upper tidal marshes reducing habitat for wildlife. Invasion of mudflats and channel edges of marshes eliminates foraging habitats for waterfowl. Human: Information not available.
Habitat: Upper intertidal zone, cobble beaches, mid to high salt marsh zone near the mean high water mark, or just below it in open mudflats.
Status and Distribution: Present in Baynes Sound on East Vancouver Island.
Management Strategy: Eradicate while populations are small and easily controlled. Seedlings can be hand-pulled; taking care to remove roots and shoots. Dig out established plants being sure to remove all rhizomes. Scattered plants can be killed by burning with a hand-held propane torch. Repeated mowing will contain growth, limit seed set and eventually kill established populations; mowing must start at initial green up and continue until fall die back and must be continued 3 to 4 years. Small infestations can be killed by mowing followed by covering with woven fabric; fabric must extend at least a meter beyond the edge of the clone and must be left in place 1 to 2 growing seasons. No biocontrol agents are presently available.
Other Common Names: Salt meadowgrass, saltmeadow cordgrass.
Origin: Atlantic Coast of North America.
Growth Form/Reproduction: Perennial grass. Seeds, rhizomes and vegetative fragmentation.
Legal Status: None.
Impacts:Agricultural: None known. Ecological: Can forms dense monocultures and has the potential to displace native vegetation in coastal salt marshes. Human: Information not available.
Habitat: Open exposed sites. Well adapted to sandy-clay soils and tolerates occasional inundations by storm tides. Primarily a plant of the upper salt marsh tidal zone; also can colonize sand dunes, sand flats and coastal scrublands.
Status and Distribution: Rare in southwestern BC, known only at Port Moody and on Vancouver Island at Comox estuary spreading into Baynes Sound.
Management Strategy: Eradicate new or small populations. Seedlings can be hand-pulled. Excavate established plants being including all rhizomes. Scattered plants can be killed by burning with a hand-held propane torch. Repeated mowing will contain growth, limit seed set and eventually kill established clones. Mowing must start at green up, continue until plants die back in fall, and must be continued 3 to 4 years. Small clones can be eradicated by mowing followed by covering with woven fabric. Fabric must extend at least one meter beyond the edge of the clone and must be left in place for 1 to 2 growing seasons. Combinations imazapyr or glyphosate with surfactants has been used in the United States to eradicate or control larger populations with variable success. No biocontrol agents are presently available.