Firstly, and most importantly, Hebes are evergreen and should be treated as other evergreens.
Most Hebes are quite happy in ordinary soil and will succeed in both acid and alkaline conditions. All varieties enjoy trimming annually, either in spring or immediately after flowering.
Hebes do not like bitter, cold winds, so a little shelter is often appreciated. Many are perfectly hardy in the south of England; elsewhere they may suffer some damage in severe winters, but many will only need trimming after bad frosts. If more severe damage occurs, your Hebe can be cut right back to old wood and still recover. You can also mulch around the base of the plant to give the main stems some protection.