ANY shrub that goes into the herbaceous border must do something for it that cannot be done by a perennial. And it can do this by colour, utility or foliage.
By definition, a shrub is a perennial, only it is one with ‘persistent woody stems from or near the base’. Some have stems that are not so persistent and are known as ‘sub-shrubs’, a classification that sounds much less attractive than the plants it includes. These behave like any ordinary border plant, dying back each year almost to the root.
