Need to nuke a yard full of crabgrass- Roundup?
My entire back yard is covered in crabgrass. We didn't realize when we moved in that the patchy "grass" in the yard was actually just weeds. I've decided what I need to do is kill most of the yard and start over (I've tried overseeding my lawn several times to fill in the many blank patches, but it's never worked. I think that might be due to the lawn being solely crabgrass, but I'm no expert).
My question is, if I hit the entire yard with round-up, will it kill the roses, bulbs, and stunted trees that are back there? If so, how do I avoid this? How long after nuking the yard can I plant vegetables? How many years will I have to apply a pre-emergent every spring before the crabgrass seeds are dead and stop coming back? Are there any alternative to this plan that DON'T require me waiting until next spring to get started? I've read elsewhere that baking soda will kill crabgrass, but I don't know if that's true, and I've only heard of it being used in the south.
I know this is a lot of questions, if anyone can just direct me to answers I would appreciate it.