We dug up our flower bed of gooseneck loosestrife and sprayed to area with Roundup. We then covered the area with a tarp to help smoother any left over plants. About a week later, we applied another dousing of Roundup and re-covered the area. Will this be enough to kill this stuff? How long do we have to wait before we plant some "wanted" plants here (azaleas)?? Thanks for your help.

In order for the Roundup to be effective, it has to be sprayed onto the foliage of plants. By your description, I'm not sure if you just sprayed the Roundup on the soil after you removed the Loosestrife. Spraying it on the ground will have no effect. If you did apply to the leaves, that would be sufficient to kill it although some plants need a 2nd treatment to kill it entirely. You should see the effects of the herbicide within a few days as the plants will turn yellow and die, which should be evident by now. If that's the case, you can go in and plant.