Hi all.

I have an area of hillside under an oak, part sun, approximately 60 feet long and about 20 feet wide at it's largest axis, and I am in the process of growing a mix of vinca and pachysandra. So far, in the areas where I have placed plants, with enough hand weeding and good soil prep the plants have filled in densely and look great. My problem is I do not have enough money or the best soil to do a single mass planting of larger starter plants and cover the whole region at once, so every spring weeds move in to the areas that aren't covered in and it gets incredibly tiresome to keep clearing them out as I plant new starters.

Are there any herbicides that would kill these weeds without harming the vinca and pachysandra that I could apply in the spring or during the summer?

Thank-you.