Use of plastic to get rid of wild violet?
I am in the process of converting my backyard from a combination of grass and "weeds" to edibles and native plants. So last Fall I used a "lasagna mulch" approach and covered several areas destined to become beds with cardboard and then a few inches of leaf-gro soil followed by leaves, compost, etc. The idea was that this would kill the grass and other unwanted plants and this spring I would be ready to put in the plants I wanted. Well, the grass and some weeds did die but I have Wild Violet popping up everywere. The cardboard didnÃ¯Â¿Â½t stop this perennial weed which is able to store quite bit of energy in its roots. So I have had to mechanically work the soil by spading it up followed by rototilling and in some cases going through each chunk of soil by hand to pull out all parts of the Wild Violet plant and through into black trash bags to die a slow death (I hope) in my garage. According to at least one thread I have seen on the Garden Web, it takes some pretty harsh herbicides to kill it and since I have a lot of edibles I decided against that route.
There is a fairly large area between newly planted trees and shrubs that I donÃ¯Â¿Â½t intend to plant on this year. I was hoping I could simply cover it with hardwood mulch but IÃ¯Â¿Â½m sure the wild violet that has already come up through the lasagna mulch would have no trouble coming up through the hardwood mulch. I really donÃ¯Â¿Â½t relish the idea of putting in the time and effort to mechanically remove the Wild Violet from such a large area. I have read that one can water an area then cover it with plastic to "cook" the soil and after a few months all the weeds underneath should be dead. In my case I would leave a bit of space around the trees to water them. Do you think this might kill Wild Violet? Should I use black plastic or clear plastic? How long would this process take? Would covering the soil with plastic be harmful to my newly planted cherry trees, blueberries, and juneberries? Does anyone have any other ideas for getting rid of this weed organically? Thanks!