Garden on a slope.
Efficient watering a slope can be difficult. Photo: Field Outdoor Spaces, Flickr

Plants growing on a slope are more difficult to water than ones growing on a more horizontal surface. That’s because the water you apply (or that Mother Nature applies) tends to flow downhill rather than penetrating the soil. And the steeper the slope, the greater the runoff and the drier the conditions! So a poor plant on even a modest slope is constantly suffering from a lack of moisture!

Watering Bassin

Watering bassin
Cut a watering basin into the slope to catch rain and irrigation water.

One way of compensating for this is to create a watering basin around each plant. Just cut into the slope on its upward side, leaving a depression. Use part of the soil to create a small semicircular berm on the downward side. This basin will help the plant catch water from rain as well as from overhead watering, allowing it to percolate slowly into the soil. Just leave the basin in place permanently. You may need to rebuild the berm occasionally, depending on the type of soil. This will give the plant a much greater share of rainfall and irrigation.

Soak Your Slope With a Soaker Hose

Soaker hose
You can also water with a soaker hose you place at right angles to the slope.

Another possibility for watering a slope is to use a soaker hose or drip irrigation, running the hose across the slope, that is, in the at right angles to the slope. Soaker hose and drip irrigation apply water more slowly and in smaller doses than other methods. It is much more likely to sink in and reach the plant’s roots than to flow down the slope, out of reach its reach.

Also, in the future, remember that slope plantings benefit less from rainfall and overhead irrigation than other plantings and will need to be irrigated more frequently.

Drought Tolerant Plants

Drop of water with prohibited symbol

Of course, the easiest way of successfully planting on a slope over the long term is to only use drought-tolerant plants in such places. They’ll still need some watering for at least the first year, but, as they root in and establish themselves, should soon be able to take care of themselves.

Illustrations: Claire Tourigny, from the book
Les 1500 trucs du jardinier paresseux by Larry Hodgson

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, will continue its mission of demystifying gardening and making it more accessible to all.

1 comment on “Successful Watering on a Slope

  1. Cascading plants on top of a slope can grow downward over a slope while their roots remain in flatter ground or a terraced area. Alternatively, plants that migrate upward can live at the bottom of a slope, where the moisture drains. Bougainvillea, for example, migrates both upward and downward.

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