You don't say where you live, but I'll give you a few suggestions. Lavenders hate hot, humid summers, but one newer variety, 'Phenomenal' tolerates that kind of climate pretty well. Plus, it repeats bloom well. If you live in a more arid summer climate, 'Grosso' is one of the very best for fragrance. All lavenders need to be pruned annually, in earliest spring, to keep them compact. I do mine the first week of March most years, shearing back almost all the previous season's growth. If you do that, any lavender can be used as a hedge. If you don't, eventually all varieties will flop open in the middle.