Most of these plants are fairly common, and their popularity stems from the fact that they are easy to grow and they shoot back quickly after being trampled on.
Shrubs and Trees
Bamboo: The taller bamboos (Pseudosasa japonica and Fargesia spathacea) provide clumps and thickets for dens. Most are hardy but dislike high winds and drought.
Butterfly bush (Buddleia): Rapidly growing plants that bloom quickly with brightly colored spires that attract butterflies.
Dogwood (Cornus): Establish fast; in winter the young stems of several varieties are a bright color. In small spaces, try the less-vigorous Cornus alba 'Elegantissima'.
Pampas grass (Cortaderia): This looks its best in groups of 3 or 5; C. selloana 'Sunningdale Silver' grows up to 13 feet high, with silver plumes.
Hazel (Corylus avellana): A small hazel thicket provides a play environment and a supply of sticks for supporting peas and making archways.
Eleaegnus xebbingei: This is a fast, tough evergreen with a dense habit that responds well to cutting back.
Hypericum: Recover well. Hypericum 'Hidcote' has a compact habit, giving dense wood for forming tunnels. Large saucer-shaped yellow flowers appear over a long period.
Kerria: Tall, graceful shrubs with green stems, which spread rapidly by suckers. Kerria japonica 'Pleniflora' has double rich yellow flowers and arching branches.
Mallow (Lavatera thuringiaca): Fast-growing elegant shrubs with grayish, downy stems and leaves; flowers produced from summer to late autumn.
Privet (Ligustrum): These recover well.
Common laurel (Prunus laurocerasus): This large shrub can grow into a small tree although it responds well to cutting back. It forms a fast-growing evergreen screen.
Willow (Salix): Open shrubs that recover well. To maintain the bright stem color, cut back hard every other year.
Elder (Sambucus): Quick to establish and tolerant. Avoid the common elder as it is rather coarse in appearance and seeds prolifically. Try S. nigra 'Aurea' or S. nigra 'Purpurea'.
Symphooricarpus: These are quite hardy and are suited to dry shade among trees. Snowberry (S. albus) forms dense clumps, ideal for secret dens.
Wayfaring tree (Viburnum lantana): A hedgerow plant that recovers well from damage. Creamy white flowers appear in late spring to early summer.
Ivy (Hedera): Many of the ivies form good dense groundcover, and are economical and quick to establish.
Periwinkle (Vinca minor): This forms attractive swathes of groundcover and has bright blue flowers. Can become invasive.
Euonymus: Come in different tones of green, gold, white and cream. They vary in height and vigor.