Creating Barriers with Plants

Gardens can be thought of as outdoor rooms; and just like the rooms of a house; each room can have a different but intentional purpose. Just as the rooms of a house are divided by walls, the rooms in a garden are separated by barriers that may be walls or fences, but can just as easily be living walls created with plants. A living wall may be a hedge or garden bed; or could be climbers growing on a trellis.
Trees, shrubs and climbing plants can in this way, all be used to provide a fence-like barrier, depending on what is required.  Trees are often preferable to a solid wall for a thick wind-break.  It offers protection while being able to "give" when fighting prevailing winds.  Shrubs, particularly those with thorns or sharp leaves, are also very useful barriers in areas where greenery is preferable to a solid fence.  And for those that must have a solid barrier, to keep animals in, etc., the use of climbing plants can soften the appearance of the barrier and help it to blend in with the rest of the garden setting.


Mounding

You need room for this but it can be very useful on larger sites, either covered with lawn or combined with planting.  Mounding of soil beds can provide a visual barrier, provide extra wind protection and separate garden areas.  It is a most useful technique, especially where an open, natural feel is desired. Mounding  is often used on the borders of large open sports ground areas, large parks or where houses as close to freeways, to create and visual and sound barrier.

Raised Garden Beds

Raised garden beds provide a combination of solid barrier, while still providing space for green life.  The perimeter of the bed can be constructed with a number of materials, depending on how solid the barrier needs to be. In some areas there will be local council regulations on the materials that can be used for a raised bed and the height, as it may contain a large mass of heavy soil wet and proper design is needed to prevent dangerous collapse of the raised bed.


Trellis

Trellis is most obviously used to create a fence (supported by posts) or dress up an otherwise bland wall). In actual fact, trellis has a great deal more uses than this. Trellis is used effectively in garden arches, pergolas, covered verandas, gazebos and many other types of garden furnishings and structures. While most trellis is timber it is possible to get trellis made from fibro cement and plastic type materials. These materials have the advantage of not rotting, though of course they do not have the same aesthetic affect found with timber.
The ease of trellisinstallation makes the cost low compared to most other types of fence. Quality varies greatly, and so does price. The cheaper trellis (often made from radiata pine) may only last a year or so in the weather. Good quality trellis maintained properly and painted (or stained) regularly will last for many years.

Hedges

Firstly decide what sort of function the hedge is going to serve. Will it be a low barrier to divide areas of the garden, or a taller screen for privacy and shelter? Will it be a formal clipped hedge or an informal hedge? Or will it be a deciduous hedge or an evergreen hedge? These factors will determine the height and the species that can be used for your purpose. Then consider which species are suitable for the garden, taking into account soil type and climate.

When you choose plants, plan ahead and think about what the plants will be like when they are fully established.
Think about the following points:

  • Choose plants that suit the climate and soil.
  • Find out whether the plants need regular clipping to keep them dense.
  • Find out the likely growth rate of your chosen plants. A slow-growing hedge may take a number of years to mature but, with good pruning and maintenance, is likely to last many decades.

Work out how many plants you will need. The spacings will be much closer than is normally recommended for plants grown in the open.

There are different times to prune hedges depending on the plant, the climate and the seasonal variations. Photinias for example are general pruned twice a year in autumn and spring. The main reason for this is to prune to encourage the handsome red growth, growing at the tips, which makes it so attractive. You can prune twice a year to get a show of these red or rust coloured tips twice a year.  Conifer hedges are usually pruned in autumn as their main growth period is winter/spring. Rose hedges are pruned at the general rose pruning time and if it is a banksia rose hedge then prune straight after flowering. As a general guide if it is a flowering hedge prune straight after flowering and well before the new growth appears, so you can direct it in the position you want.  If your hedging plant is frost tender then prune outside of the frost period as well. For slow growing plants like the box only occasional or annual pruning is necessary while privet may be pruned a number of times during spring and early summer when it is actively growing. If you are dealing with very vigorous plants and the climate is not frosty and it is a plant not grown for the flowers, then you can prune anytime.