Permanent Vegetation States

It would be nice to be able to stop the growth of vegetation.

This would mainly be an esthetic change which would allow for variation in for example crop fields. But it would also be great for stopping vines and such to grow out of control, as I know a lot of people (myself included) refrain from using them at all since they end up spreading everywhere.

My suggestion is to use perhaps a combination of slime and poisonous potato to make "Poisonous Slime" or something of the sort. Which would be used on vegetation similar to how wax is used on copper stopping it from aging.