Here are some savvy solutions to overcome the challenges of hillside gardening, including erosion
Gardening on a slope can be a challenge, but for those who get it right, the slope becomes a major asset and helps bring together a design which is unique to that garden.
A number of factors make hillside gardening especially difficult. Gardeners are challenged by soil erosion, drainage problems, dry soil at the top of the slope, or very sunny and shaded areas, depending on the location of the property.
Top South African landscapers are often called in to help property owners with the challenges of slopes.
Peninsula Landscaping’s Colin de Wet says the gradient is the most important aspect to consider when evaluating slopes. Gentle slopes are easier to work on, while those with a much steeper gradient usually require professional assistance.
“Correct stabilisation is essential, especially where the slope is particularly high and steep,” he says. “If it is gradual, the risk of erosion or a landslide is reduced.”
How can you stabilise the slope before planting?
“First level and fine grade your embankment, then spread compost and cultivate the area in preparation for planting,” says De Wet. “Place geo-jute, a bio-degradable fabric, on top of the slope and peg it to the embankment to stop erosion.
“Position and secure poles (with pegs) about 1.5m apart, down the face of the embankment. Cut slits in the fabric and plant into the prepared soil below.”
Another method to consider is to first level and fine grade your embankment, cultivate the area for planting and then lay strips of roll-on lawn horizontally across the slope and peg in position.
“Pockets can be made in the grass and plants can be planted in the pockets,” says De Wet. “Once the embankment is stable, you can remove the grass if needs be.”
Smart slope solutions
How can you create a functional, yet aesthetically pleasing hillside garden? Consider these four tips from De Wet.
Build a retaining wall
On slopes, retaining walls help keep soil in place and prevent downward movement, but they also provide an opportunity for an exciting design within the garden.
“Gabion walls are an attractive choice for retaining walls. One could then pocket plant randomly between the stones to create a natural effect,” says De Wet.
“When using cement blocks as a retaining wall, these look best if filled with a decent soil-compost mix and then planted with hardy indigenous shrubs that cascade and cover a large area.”
Good plant choices include Arctotis sp, silver bush everlasting (Helichrysum petiolare), sour fig (Carpobrotus edulis) and the lobster flower (Plectranthus neochilus).
The space alongside high retaining walls also creates a feeling of privacy which makes a good location for a garden patio or secluded reading corner.
The practice of dry-stacking stones to create a wall is centuries old. Stones or slate are stacked without mortar and are held together by the sheer weight of the rock. Always get advice from an expert before constructing this type of wall.
Choosing the right plants is an important aspect of gardening on a hillside. While plants provide greenery and colour, their roots help to anchor the soil.
Fynbos works well on a sunny hillside with a gentle slope. De Wet says agapanthus, sour fig (which spreads fast and covers a large area) and arctotis are also worth considering for hillside planting.
“If you are planting in geo-jute, you could plant just about any waterwise shrub,” he says.
Create a journey
Stairs and pathways may be a necessity on a slope to access areas of the garden, but they can also be used to create a journey that takes the visitor through a series of garden rooms down the slope and leading to something special below.
Here you could place a garden bench to watch birds, a statue, bonsai benches which showcase a collectionor a fire pit. Place containers of your favourite scented plants at the sides of the steps, to engage the senses as you move along.
“Consider steps if the area is too steep to walk up naturally,” advises De Wet.
“Avoid placing steps in a rocky area unless the natural form of rocks is suitable for steps. Depending on the theme and space, various materials can be used for steps, including wooden sleepers, upside down terraforce blocks placed or concrete.”
Long, steep slopes are best dealt with by terracing. The terrace brings a gradual decline in the drop and the spaces between drops provide the gardener with flat ground for planting. Consider a garden patio on one of the higher levels, from which one can enjoy a delightful view.
Terrace walls on steep slopes are best handled by a professional landscaper, as the walls must be reinforced and accommodate weep holes and piping for drainage.
A terraced garden also provides the perfect position for your favourite cascading container plants along the walls. For more more info, see https://www.penland.co.za/