One of the problems with plugs (rather than growing herbs and plants from seed) is that even once transplanted, they are sometimes quite sparse and patchy in their new home. In my herbal vertical garden planters some of the plants, parsley and thyme for example, have really taken off and have spread wonderfully to fill their little beds. But some, like the mint and rosemary, have simply grown very long and straggly. So in an attempt to encourage them to bush up a bit I've cut the growing tips and hope that they'll start to grow out rather than up. Fingers crossed!