Shrubs, the term does them no favours, yet shrubs are a fantastic group of plants that are valuable in so many ways.
What are shrubs?
Shrubs or bushes are woody plants that branch in or close to the ground. Unlike trees, they generally do not form a clear trunk, but most species develop a number of stems, known as basal stems. Size does not determine whether a plant is a tree or a shrub. Some shrubs grow very tall but most do not grow above three to four metres.
There are also some shrubs that occupy a grey area between the two. The sumac tree (Rhus typhina), for example, actually forms a large bush.
What are half-shrubs?
These are shrubs which originate from a climate other than ours and where the young shoots only go woody in the following year and are therefore extremely frost-sensitive initially. When they are grown in our climate, they can be badly affected by frost. Examples include lavender and Ceanothus.
Shrubs may be divided into evergreen and deciduous, as well as by growth habit, position and use. There is a shrub for every situation because of their diversity. There are even climbing and trailing shrubs (these are grouped in with climbers).
Growing shrubs in combination
A great rule of thumb for combination planting is to use one evergreen for three deciduous shrubs (excluding hedges). Shrubs and trees form the permanent framework of the garden, around which other plants are grouped. It is this combination which makes a garden dynamic and interesting.
Perennials look best in front of a tranquil green backdrop. Also pay close attention to the height and spread of the shrubs, so that you avoid pruning problems later. It’s also a good idea to think about the decorative value of the plants when they are not flowering or in leaf. Try to combine plants with as many pleasing characteristics as possible, particularly if you only have room for a few.
Relate the shrubs you choose to the conditions where you are planting them to ensure success. Shrubs’ requirements are usually shown clearly on the labels. Make sure you study these. Some species must be placed in full sun positions, and others that prefer more shade. The soil type is also important.
Species like Rhododendron, Erica and Calluna like acid soil (pH lower than 7), whilst lilac and Buxus - for example - prefer alkaline soil (pH above 7). The dampness of the soil is also important. Most species are suited to normal garden soil with normal levels of soil moisture. Only if there are clear deviations does this need to be specified with the plants.
What needs protection in winter and how?
Some shrubs popular in this country can’t cope with our winters. These have to be grown in pots and troughs and brought in to frost-free, light places, such as conservatories. Other species will tolerate some frost and can survive a mild winter outside (even when planted in the soil). These are species like bay, Fatsia and the like.
They are plants which store little sugar in their sap and therefore freeze easily. They do need to be protected against harsh frosts. Wrapping some horticultural fleece around them is the perfect way to do this