I live in zone 4 and am looking to plant a neighbor's patch of dirt with a no-mow type of grass(per her request). Is there such a thing and will I have to put in a barrier to keep it from invading my adjacent flower bed? As a gardener I've come to regard grass as flower bed enemy # 1 but am holding out hope for a type that is available in seed and won't spread out without me having to mulch heavily my side of the garden. Your input is greatly appreciated.