Yes, it sounds like your heather could use a shearing. Cut heather with hedge trimmers removing all the faded blooms which usually means taking about the top third off the plant. Rather like giving them a crew cut. Poke your finger in a feel the soil. Do not water until the top inch of soil is dry. Heather can handle full sun but if they are newly planted it may take a year before they have enough roots to handle intense heat. One tip is to bring out an umbrella to shade newly planted shrubs if a heat dome arrives for a few days. Keep growing, Marianne Binetti