How to Design for a Sloping Garden

A sloping site may often feel like a challenge. But there are plenty of ways to get around any problems, and to find opportunity in the options a sloping garden can provide. 

Observe the Slope & Determine the Aspect and Gradient

You can’t do much with a sloping garden unless you first take a good long look at what exactly you are dealing with. In order to solve any potential issues with a sloping site it is first important to identify them. 

Taking some time to look at the slope can help you to determine its properties, and find opportunity in the challenges you discover. 

Aspect and gradient are two of the most important things to consider. The aspect of a slope is the direction that it faces. And the gradient is how steep it is. Each of these things are key in determining the best solutions for the particular sloping site. 

Of course there are other factors to consider, such as the soil properties, existing vegetation, and the climate and microclimate where you live. But looking at aspect and gradient can be a good place to begin when finding the best solutions for your garden. 

South Facing Sloping Garden

South facing slopes are often less challenging to design for than those which have another aspect. These receive the most sun, for a longer period during the day (in the northern hemisphere). They are not as shaded. 

However, because they receive more sun, they can be more likely to dry out, especially in warm conditions. If the soil becomes too dry. It may be more likely to experience issues with erosion, especially in areas where there is a lighter soil type. 

In the UK, the prevailing wind direction is often from the south west. So another potential challenge is that south/ west facing slopes can often be more exposed. Winds can exacerbate erosion issues, and be drying too.

West Facing Sloping Garden

West facing slopes may also often be rather exposed to prevailing winds in the UK, and also receive sunlight during the afternoon – usually the hottest part of the day. They will usually be shaded during the morning hours but may bake on warm summer afternoons. 

However, exposure to the sun in the afternoon can also be beneficial – both for plant growth and when human amenity is considered. A west-facing slope, for example, might be the perfect location for a seating or other outdoors area to enjoy after work. 

East Facing Sloping Garden

East facing slopes receive sun in the morning, but are typically much more shaded during the later part of the day. Frost pockets may sometimes form towards the base of such a slope, causing issues for more tender plants. 

More shaded than south or west facing slopes, however, east facing slopes will often dry out less quickly. And may be good spots for enjoying a morning coffee break, for example.

North Facing Sloping Garden

North facing slopes are typically the most challenging, because they will usually be far more deeply shaded. They will often be chillier, and can often be wetter due to the increased levels of direct sun. 

However, when the right decisions are made, the moisture and the shade can be viewed as beneficial. And the terrain may protect the area from winds and make for more sheltered spots at its base. 

Gentle Slope – Slowing Water Flow, Preventing Runoff and Erosion

Aspect determines the sunlight and shade on the site throughout each day and throughout the year. This will have an impact on water, and its availability or excess. 

With more gentle slopes, shading will typically be less pronounced, water will flow more slowly, and run off and erosion will typically be less challenging to manage. Slight slopes are not always an issue – you can even build a polytunnel on a slope, providing the slope is not too extreme.

However, one key thing to consider, even on a gentle slope, is that water will flow downhill. To manage a sloping garden in a sustainable way, we should consider how we can catch and store water in the garden – slowing and directing water flow to keep it around in our gardens, and prevent runoff and soil erosion. 

Where slope is gentler, and the gradient less pronounced, it can sometimes be helpful to consider undertaking earthworks which help us catch and store water in the landscape – especially in drier areas and on areas which dry out more quickly. On-contour swales and berms, which follow level routes across the slope, can sometimes be used to slow water flow and keep water around for plants growing on a gentle slope, for example. 

In a sloping garden, you may also sometimes find that excess water is a problem – running down the slope and pooling or causing waterlogging at the base. French drains and other earthworks can help to direct excess water to areas where it can be used. 

It is important to remember that vegetation – the plants on a slope, are also key to keeping the soil healthy and in place, and preventing runoff and erosion on a sloping site. Vegetation will slow the flow of water, soak up excess, and help to prevent flooding issues. 

By combining deep rooted species and shallow rooted ground cover plants, we can anchor all layers of the soil and make sure that there is stability on the terrain. 

Steep Slope – Amending the Gradient

In certain circumstances, where slope is more pronounced, we may wish to consider more dramatic measures to improve a garden. Terracing steep slopes, for example, can slow water, provide more planting space, and also provide more usable amenity spaces for you and your family. 

Terraces can be retained in a range of different ways – with stone walls, gabions, or with logs or fences, for example. There are plenty of opportunities to think about how you might retain new contouring with natural or reclaimed materials which also add visual appeal to the space. 

Steep Slope – Finding the Opportunity

If you do have areas with a steeper gradient in your garden, it is also interesting to consider that there may be ways to see the slope as an advantage and find opportunity in the terrain. 

For example, a steep south facing slope may provide the opportunity to create earth sheltered structures like greenhouses or summerhouses built into the slope. This allows you to take advantage of the thermal mass of the earth behind, while making the most of the sun exposure. 

In a shady north facing slope, you might be able to create earth-sheltered root cellars, or cold storage areas. 

Another thing to consider is that a steep slope with any aspect might also give you the opportunity to gravity feed water for irrigation or other purposes to other lower parts of your garden. You might also be able to create attractive water features – for example – create upper and lower ponds with a waterfall cascading between them. 

Sloping sites can often seem like a challenge. But they can also give some excellent opportunities to create thriving, beautiful and productive gardens.