Shrubs do the structural work in a landscape. They are what fills the space between the trees and the ground, what screens a view, what softens a foundation, and what a bed looks like in February when the perennials are gone.
The question that decides a shrub is mature size, and it is the one most often got wrong. A plant that comes off the truck at two feet and is rated to eight has made a promise, and in five years it keeps it — against the walk, over the window, into its neighbor. Spacing a bed to mature size looks sparse the first year, correct in year three, and like the drawing by year five. That gap is where most of the pruning-forever problems in this valley get created.
Beyond size, the divisions below are the practical ones. Evergreen shrubs hold foliage and keep a bed from emptying out over winter, and they work hardest at the time of year when they are most exposed. Deciduous shrubs give you flowering, fall color and a wider range of plants that tolerate this soil. Roses are their own thing and have their own page.
Worth knowing before you choose for a screen: a great many shrubs sold for screening are solid at eye level for eight years and then go bare at the bottom as they mature. The useful question is never how tall it gets. It is how dense it is at the height you actually need it.
