I agree sometimes you just need to clear the land quickly for access or building, but I've never had any success getting rid of them permanently except by poisoning them when they are growing strongly - especially if you don't want to poison the soil itself. So, if you are going to end up with the front yard producing grass, I doubt you can do much more than slash them and wait until they get up and running in spring. Even then, you may not catch them all growing simultaneously so soon after slashing, and there will be lots of old seed laying around, so they'll keep coming back for a few years. And I'm sure you know all that.
