A woodland garden strives to recreate the informal style of wild or natural shade plantings found in the woods. A more formal style could include structured planting beds of tender shade annuals. Existing canopy or overstory trees form the ceiling of a shade garden. Start planning the garden in these areas with understory trees and shrubs, then move to the herbaceous plants. Understory trees bridge the gap between the canopy and shrub layer, duplicating the natural structure of a forest and providing wildlife habitat.
Small trees provide a sense of enclosure and a backdrop for the rest of the garden.
Shrubs can be thought of as the walls of a garden room. Include them with understory trees to form an uninterrupted line that flows into the tree canopy. Shrubs can be used to screen unattractive views like driveways and service areas, even the neighbor's trash cans. Shrubs provide privacy and can be used to create secluded nooks and woodland hideaways. Planting a massing of shrubs at the curve of a path can create an air of mystery.