Depends on what hebe you have too. I grow hebe salicifolia....hope got that right.... A tall plant with wands of white flowers, full flower right now, and I remove all the flowering shoots plus a general tidy up for shape and size as soon as flowering is over. I do this with gauntletii And with the smaller variegated hebes. Keeps them young, fresh and mounded. These hebes grow so quickly that they do get leggy before you notice it.