Control of snow on mountain and canary grass
If the plants are still green, they are still susceptible to Roundup. Glyphosate (Roundup) is a recommended method for controlling reed canary grass.
Glyphosate will also work on Aegopodium podagraria (snow-on-the-mountain), although it will take several applications. Do it now, then again in the spring.
Remember that Glyphosate will kill anything green it touches. Always follow the label.