vinca minor groundcover - should I put down Preen at planting?
I am planning to have part of a slope planted with vinca minor (currently there are junipers but they have not had enough sun and have done badly so will be ripped out). As I understand it vinca minor spreads by rooting where the spreading stems touch ground, so we'll probably use only half an inch to an inch of mulch. That leads to my concern about weeds until the vinca is fully spread. Does it make sense to put down Preen before the mulch, or would that also inhibit the spread of the vinca minor?
Thanks in advance for any advice.