Post category: Shrubs
Shrubs are relatively low-growing woody plants, ranging in height from a few centimetres to three metres or more. The majority of shrubs are rounded in outline, but shape is very varied – upright, rounded, flat, drooping, and prostrate.
Shrubs of different sizes can be used in two ways. In big gardens, large shrubs are used to fill in around trees. In small gardens, large shrubs such as philadelphus, buddleia, tamarisk, pieris, lauristinus and forsythia, might take on the same role as small trees, creating a planting ‘backbone’.
A tree has a single trunk; a shrub has numerous stems at ground level. Nature is not clearcut, however, and while there are trees such as hazel that often produce several stems, there are also shrubs such as broom and hebe that have a single stem. Neither is it a question of size. Certain japanese maples are small trees while the much bigger buddleia davidii is always a shrub.
True shrubs tend to regularly produce new shoots from low down on their stems, or even from their roots. But there are suckering trees as well. In general, shrubs tend to be less woody than trees, more twiggy and their wood is not as hard.
Shrubs are the next layer of woody plants, a step down from the garden trees. Some are native to woodland – they are forest shrub layer plants. These tolerate shade to varying degrees. Examples include rhododendron(as shown), camellia, snowberry, cherry laurel, viburnum, aucuba, osmanthus. Notice that many of these are evergreen, taking advantage of the light before the canopy comes on the big trees.
Many shrubs are plants of open ground, in both dry and wet habitats, where there are few trees or no trees. Heathers, juniper, cistus, lavender, thyme, broom, cotoneaster, berberis, roses, potentilla are examples of those which enjoy sunshine and well-drained soil. Dogwood, shrubby willows, sambucus, and some spireas enjoy damp soil.
Shrubs are used to fill out the ‘backbone’ of trees. Shade tolerant types can be used to fill the space beneath trees; those which like more light can be used in borders in front of trees, hiding their bases.
Shrubs have tremendous variety of size and shape, flower and leaf colour, season of flowering, leaf size and shape. The challenge is to plant shrubs so that they associate well with trees, other shrubs and herbaceous plants.
While shrubs are best used with some trees to give height and some flowers to give colour and lush foliage, shrubs can also be planted on their own in some circumstances – for instance, to fill out a piece of ground – or they can be planted just with trees, or just with some flowers.
To space neighbouring shrubs, add together the expected spread of the two species and divide by two. Dividing by three gives a closer spacing and quicker fill-in. The latter estimation is more suitable for groups of the same plant and for the shorter-lived kinds. Long-lived shrubs, and the more choice kinds like rhododendron, magnolia and pieris, should get the wider spacing.
Shrubs must be planted in conditions that suit them. Some require acid soil; others, dry soil, damp soil and so on. Most kinds like a sunny position and good soil, even those which tolerate some shade. Feeding is worthwhile at planting and every spring for a few years until they are established.