Shrubs and Trees can be pruned to the desired shape and size depending on your needs or garden style.
Prune off the spent flowers and trim branches to the desired shape. Cutting the tops of branches will encourage the plant to make new side growth.
Remove any dead or damaged branches at ground level. This will give new growth the room it needs. Prune old and misshapen branches out to increase air circulation and allow light to reach the center of the shrub.
Perennials are plants that in general, die back to the ground at the end of their growing season. You can cut back the spent growth to maintain a tidy appearance or you can leave it through winter for structural interest and clean it up in the spring.
Grasses can be cut back at the end of their growing season to clear the way for new growth in the spring. If you prefer, you can leave grasses alone through the winter which provides structural interest and a nice bird habitat.
Vines can be trimmed throughout the season to maintain a desired height and size.
Groundcovers really don't need any pruning maintenance at all.