Landscaping slopes is one of the more challenging landscaping projects you will attempt, but if done properly, this will also be one of the most rewarding projects anyone can ever do.
In Cape Town, most of the homes close to the ocean lie against a slope of some kind or another, with amazing views towards the sea. Just look at the view from one of these Clifton beach homes!
When contemplating landscaping against slopes, there are a few things that must be taken into consideration and a few others that should be kept in the back of your mind. This will just make the complete experience much more enjoyable, as mistakes can be costly and dangerous.
The things to consider:
Cape Town has massive fires each year and hillside homes are much more vulnerable than homes on lower, level ground.
Heat rises and with the winds that we get in Cape Town, a fire like the one you see here can move at an incredible speed and devastate massive amounts of land and property in a very short space of time.
Contemplate the following points when you are landscaping slopes.
Many people buy their hillside homes for no other reason than the view they get from the property. The home in itself may not have been the initial reason for buying the property, and neither the garden nor the landscape.
And I am sure that if you have a view from your property, it is just as important to you as it is to me.
Therefore it is imperative that you enhance your view when landscaping slopes.
One thing that makes landscaping slopes a bit easier than when designing a flat garden, is the fact that you don't have to force the site. You have natural slope which means that you can create the effect of height and space and private places more easily.
It provides you with an opportunity to create something spectacular to add to the views from your home. Rock gardens, water features and colour can be blended into the slope for maximum impact.
It may be worth your while to use a designer when planning and designing your landscape against a slope, as experience comes in handy when you have to consider the things I mention below.
If you are going to use high and extensive retaining walls, it is very important to get some expert advice.
and I mean real expert advice, not the gardener's or the guy that helps at the nursery.
There are laws in place that has to be adhered to when constructing retaining walls and an engineer specialising in this type of work will be my suggestion.
Soil and water exert pressure against a retaining wall and if not properly designed and the correct procedures followed during construction, the walls will fail at some time and cause massive damage to the area below the wall.
A retaining wall design has to account for a number of factors and what you need to understand at this stage is that these forces exist and I recommend the services of a specialist.
When working with steep slopes, it is very important that you plan your design to the "tee". Even when you are not building a retaining wall, there are always natural forces that may cause your slope to move and these must be kept in mind as it will have an impact when you landscape slopes.
Soil comprises of layers and when you build on, or landscape slopes, you may compromise the natural binding of the soil layers. When heavy rains then fall, the rain soaks the earth and the lack of cohesive qualities (meaning not sufficient binding) between the layers, will cause the soil to wash away.
It is therefore important to plant shrubs, trees and other vegetation that have a deep network of fine roots. This network of fine roots is still the most effective way to quickly restore the binding between the layers of soil.
Remember that anything heavy you add to the slope, such as boulders, water features and trees will add weight so it is important to stabilise them to reduce the force they will exert on the soil.
Proper drainage is key when landscaping slopes. Small amounts of water act as a binding agent for the soil (think of building a sand castle with dry sand compared to wet sand), but too much water has a damaging effect due to the forces they create.
Plants that need a lot of moisture will also help to stabilise the slope or bank by using some of the water that contribute to the movement of the soil.
Water control is therefore important to avoid erosion and "land slides" .
I never use anything that needs "active" maintenance when I landscape slopes; like a lawn for example. It needs to be mowed and that is difficult against a slope.
I much rather use ground cover, which also needs much less water and little maintenance.
Terracing is an excellent way of landscaping slopes. They are easy to maintain and you create stunning areas which you can access by stairs.
Another effective way of landscaping slopes is to build rock gardens. It is affordable and can be a great focal point while at the same time stabilising the soil with grasses and ground cover.