Herbicides and food safety
I need to eradicate non-native, invasive annual grasses (barnyard grass & crabgrass, in particular). The grasses are among a plot of wildflowers and native perennial grasses -- these are much shorter than the already well-grown annual grasses I wish to get rid of. Unfortunately, the area is too large for hand-weeding.
*As carefully as practical, brush/mat Roundup (glyco-phospate) onto the upper portion of all the annual grasses and broad-leaf weeds I can, without going too low to the ground, which is where the native stuff I seeded in the spring is growing.
*Use a product such as Envoy or Agrisel's Grass Out Max which contains Clethodim. This will kill all the grasses I don't want, and a bit of the native grasses I wanted (which I can replace in the fall). This would mean that I still have to hand-weed the broad-leaf weeds, which are way easier to remove in most cases than the grasses.
I will be spraying plants that are near enough to perennial edibles (strawberries, etc.) and where I have garden pond that I intend to stock amphibians into, in the future. I don't need to eat any of the edibles this year; I can hold off until next year, if that's a concern to consider.
I'd rather go with the Round-up (glyco-phosphate) strategy if this is much more environmentally safe. As far as I know, Round-up will cease to be toxic to the environment in a relatively short time following application. It seems to me that frogs will not be damaged by it, being introduced one year following application. As for Envoy or Grass Out Max which contain Celthodim, this could be a problem -- could it be?
I'd rather do more work than cause lasting ecological damage to my yard; it's a native plant/wildlife reconstruction feature -- 1/4 acre.