Search any botanical book looking for a scientific name or definition of a 'shrub' and your search will be in vain. Shrubs are colloquial for 'plants we can't define'! They're not trees. They certainly don't grow as annuals and you won't dig them up each year like bulbs. Yet, they are so much a part of our garden that without shrubs our landscapes would be hideously bare.

They're the filler like cream between layers of sponge cake. Everyone talks about the sponge but without the cream our tongues would be smacking our jowels in search of moisture.

But shrubs are more than that. In many landscaper's vocabulary, focal plants are the sponge cake of any garden. Their perspective on shrubs is to highlight the specific plant that somehow needs special attention - what if, that focal plant was a shrub? No, what if it were shrubs, plural?

Ok. Now you're working with me...this is great. Imagine your garden is a vista of colour, shape and texture and not an annual or a bulb were in sight - not that I'm against either. Evergreen shrubs contrasted against their deciduous counterparts. Brilliant flowering shrubs took the stage while more humble foliage plants helped contrast their beauty for one season and then reversed roles in the next.

Now you're getting a picture of what shrubs can do for your garden.

The Difference between Shrubs and Trees

Definitions of 'shrubs' abound but I think the most succinct one is this;

Woody perennial, smaller than a tree, usually with multiple stems.

It captures definitively what a plant must be to be called a 'shrub'. Shrubs are not trees although often you might hear a plant being described as a 'shrubby tree' highlighting its growing habit and the height it may have.

Trees usually have one central trunk that rises to meet its foliage while a shrub is often multi-stemmed and wrapped in leaves. Trees often start at 5-6m while shrubs usually end at this height. However, shrubs are similar to trees in that some species are deciduous like dogwoods while others remain evergreen. Some flower and others may not, or their flower is insignificant.

How to grow shrubs

It all depends, of course, on your specific climate, soil type, altitude etc as to how to grow shrubs. As they're not a specific genus the term collectively represents everything from a proteaceae to a virburnum; a heather to a rhododendron. So, to give specific how-to instructions would be like trying to lasso the wind - any advice could be spot on or it could miss the mark by a football field.

However, planting a shrub is fairly standard as too is pruning them. Pruning shrubs should be performed either at the end of the flowering season or just prior its growing period. And, it is usually recommended that the shrub is pruned by a third or at least to shape.

The best way to find shrubs that will grow in your area is to drive around and see what other gardeners are having success with. This shouldn't exclude your pioneering spirit but it will help you to understand the shrubs that grow well and will probably have less chance of disease or pest infestations.

Propagating shrubs

Many of our shrubs are very easy to propagate and there are a few methods that would offer some success. Collecting and germinating seed may be possible with some shrubs but this is probably the least preferred method of most home gardeners because there are quicker and more successful options available.

• Air & Soil Layering - these two propagation methods work well with shrubs as their multi-stems and branches offer some easy to work with material. The success depends on the shrub and how temperamental it is to being cloned.
• Softwood Cuttings - many shrubs can be propagated this way and it works well with hebes, lavender, vibrunum and heathers.
• Hardwood Cuttings - similar to softwood cuttings except that the propagation material is collected after flowering has finished or during the shrubs dormant period. This is a great technique for dogwoods, azaleas and camellias.

So, if you've always thought of shrubs as being the filler plants in your garden, maybe it's time to take a second look. Just maybe, they could provide another level of interest that you haven't explored yet.