Slopes that are steep are a challenge for most gardeners. They are often difficult to amend, plant, water, and fertilize, and are likely to erode. By their grade, these slopes can also create other problems, such as low fertility, lack of soil moisture, shallow soils, and erosion.
Creative ways to handle steep or hilly gardens center around construction and earthmoving solutions. Terracing, adding permanent containers, carving out plant niches, and using some specially adapted plantings are valuable alternatives.
Watering on slopes is difficult because the water tends to run off instead of sinking into the soil. Drip irrigation is a good solution. Use pressure-compensating emitters to handle the differences in elevation.
Taming a Slope
The simplest solution to a steep spot is to plant the hillside with a ground cover. Sprawling vines and groundcovers that root as they grow are naturals for hillsides. If necessary, spread straw mulch or pine needles and hold it in place with erosion netting. Plant through the holes in the netting. The straw and netting will prevent erosion until the ground cover is established.
Small individual planting holes can be scooped out of the slope and treated almost as a planting container. Small basins are created in the sloping soil, given lips to hold water and planting material, and then planted with small to medium-sized plants. Alpines look nice on rocky hillsides.
Terraces are good solutions for breaking up the downward plunge of a steep slope. Select timbers, stones, or any sturdy material that makes a good retaining wall and can be moored securely on the hillside. This solution is expensive in dollars and effort, but gives the most satisfactory solution.