Tuesday 13 March 2012

WHAT IS A SHRUB?




Trees and shrubs are both woody plants that are very similar in appearance.  Shrubs differ from trees as they do not have a single, clear trunk but instead are multi stemmed near ground level. Shrubs are usually shorter than trees, below 6 metres, with stems of a diameter less than 8 cm diameter. They have several perennial stems that may be erect or may lay close to the ground, although none of these stems will be dominant.

There is a degree of overlap between shrubs and other plant groups. A number of plants can become shrubs or trees depending on growing conditions. Lilac (Syringa) is a shrub that grows on a single stem. Some trees such as Japanese maple (Acer palmatum) have multiple trunks.  Shrubs may grow to the size of a small tree. Cornus mas, the cornelian cherry, is described as a shrub although it grows to 8 metres. Malus sargentii, the sargent crab apple, grows to 4 metres but is considered a tree.

Shrubs can be deciduous or evergreen, and are generally broad leaved plants with the exception of some small conifers such as juniper. Small low shrubs such as lavender, periwinkle and thymes are only woody at their base and are termed sub-shrubs.

With their fragrant flowers, striking fruits, decorative stems, attractive foliage and architectural habits it is no wonder that shrubs are so popular. Naturally growing in a wide spectrum of habitats, there is a shrub suitable for every soil and aspect.

Some shrubs such as witch hazel (Hamamelis) have stunning autumn colour with leaves turning from yellow through to orange and red. Others have a profusion of small flowers which cover the stems completely (Ceanothus), whilst others have giant blooms (Paeonia). Some shrubs such as holly (Ilex) and Pyracantha bear decorative berries during the winter. Dogwoods (Cornus) display bright winter stems which range from vivid red to bright yellow.

Many shrubs respond well to pruning back to a central frame. They can also be shaped into tight forms through topiary as they have dense foliage and close branches. They can be used as hedges, screens and background plantings. Often they are grown in a shrub border or mixed border among annuals and perennials.

For related articles click onto:
What is a tree?
What is a potager?
What is a vegetable?
What is the difference between a conifer and a deciduous tree?
Which plant has the largest seed?
Which plant has the largest leaves?
Which plant has the largest flower?
Vegetable crop rotation

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