People see challenges where others don’t. Take a large slope, for example. Some homeowners who have a sloping front yard, side yard, or backyard may be inclined not to get involved in creating a garden on it. When there is a heavy rain, a torrent of water streams down from the top of the slope and tends to wash everything out. If plants were present, they would most assuredly get washed away and end up in piles at the bottom of the slope.
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And when conditions are dry and hot, the soil on a slope gets exposed and parched. It just isn’t capable of holding enough water for plants to establish themselves.
Some gardeners would inspect the area and decide it’s best to leave it alone. While some other gardeners may feel that gardens can be created anywhere, even on a slope. They’re so sure of their gardening skills that they decide to take on the challenge.
Overcoming the challenge is possible. With the right kind of plants and a proper method of allowing the plants’ root system to establish, a garden can indeed take root on a slope.
The project may be difficult and involve some pitfalls, but the goal of creating a garden on a slope can be achieved.
During my research I discovered two methods that make planting a garden on a slope possible. One uses jute erosion-control netting and the other rely on the creation of terraces.
Jute Erosion-Control Net Method Of Establishing A Garden On A Slope
The items required to establish a garden on a slope using this method include:
• Bark Mulch
• Jute Erosion-Control Netting
• Sharp Knife
• Shovel
• Plants
• Drip Irrigation System
Select plants that feature strong, dense roots. The root system of each plant will not only keep the plant in place, it will also keep the soil in place.
Plants that are suggested for this project include wild lilac, creeping mahonia, juniper, rockrose, and any species of Artemisia or cotoneaster. Shrubs that you can use include flowering quince, St. John’s wort, and sumacs. Groundcovers you can use include periwinkle, rugosa rose, “Gro-Low” aromatic sumac, and crown vetch.
Your collection should include a large variety of different sized plants that you can spread out to disperse rainfall. Once the root systems are established, it will be impossible to wash out the soil and the plants.
Start off the project by spreading bark mulch about 1-inch deep on the entire slope.
Next, cover the slope with the jute erosion control netting.
Decide where in the netting you want to plant the flora, and then use the knife to cut an “X” into the netting where you want a plant.
Peel back the cut surface of the netting where each plant will be installed.
Spread another inch of bark mulch over the jute netting.
Install the plants. Consider staggering the plants in horizontal rows along the slope instead of aligning them.
Install a drip irrigation system at the top of the slope to limit the amount of water that flows down when the plants need water.
The Terrace Method Of Establishing A Garden On A Slope
Items you will need for this project include:
• Shovel
• Topsoil
• Plants
• Perlite, Coarse Lava Rock, or coarse builder sand or biochar and other organic matter depending on your soil type.
• Compost
Select plants that feature clumping roots. This type of root system will help to secure the plants into the ground. Plants with clumped roots include trees, shrubs, and grasses like Indiangrass, Little Bluestem, Wild Bergamot and Creeping Flox. Groundcover including St. John’s Wort, Creeping Raspberry, Purple Ice Plant, and Georgia Blues Veronica can be used to fill spaces between other plants.
Survey the slope and decide where you want the terraces to be and analyze the soil to determine its type. Knowing the type of soil you have, whether it’s sandy or clay, will help you select the proper plants to use in the garden.
Once you know the type of soil you have, add organic matter to make it healthier. If your soil is heavy clay, add some perlite, coarse lava rock, or coarse builder sand and compost. This will increase the porosity of the soil so it will drain properly. If you have sandy soil, then the bacteria and other organic materials filter down because there is no place for that stuff to settle. Add biochar and other organic matter so that the bacteria have a surface to grow on.
When creating the terraces, dig about 6- to 12-inches into the slope to create a level area. And continue this down the slope. The exact depth of the terraces depend on the length of the root of the plants you select. When you install the plants, the roots need to be fully covered with an additional inch or two of soil.
The terrace effect provides a leveled off area in which it is easy for the plants to grow. Growing through a flat surface is easier than growing through an angled one.
Don’t dig too much soil at once. It may cause the ground to become unstable.
As you build the terraces down the slope, alternate between berms and swales. The berms are built up areas of soil and the swales are depressions in the soil. The depressed areas are the terraces.
When installing the plants, dig down about 6-inches to 1-foot into the soil. Place the plant in the hole and then build up the soil in a half moon shape below the plant. This will assure that each plant gets enough water and assures the root system of each plant establishes and thrives.
Strategically place the plants on the slope depending on the water running down hill. Drought resistant plants should be installed at the top of the slope. Plants that need a lot of water should be at the bottom of the slope.
If you wish, you can create a retaining wall at the bottom of the slope consisting of ground soil or rocks, but it isn’t necessary. You could opt for a constructed retaining wall instead.
If you use ground soil, then you should use extra topsoil of about 6-inches to 1-foot to create the berm.
If you rather have a rock wall, then you should stack the rocks to a height of about 6-inches to 1-foot off the ground. Be sure that you dig a depression for the rocks on the ground of at least one-third the length of the rocks you use. The depression or notch will keep the rocks anchored to the ground so they won’t slide down the slope.
Once the garden is planted, then you have to care for it. Add mulch to enrich and support the soil. It keeps the soil healthy, prevents it from spreading and helps it to retain moisture.
Best mulches for slopes include lava stone or pumice rock, rock mulch, wood chips and shredded bark. Choose the mulch that will best retain moisture and match it to the terrain. For example, if you’ve planted several trees or live in a forested region, use wood chips or shredded bark.
Spread the mulch at the base of each plant and also put between rocks of your retainer wall. The heavier the mulch, the less you will need. It’s best to mulch 4-inches up from the base of the plant.
If you use organic mulch, keep in mind that you’ll have to replace it every year or so. That’s because it will break down and be absorbed into the soil.
Finally, inspect the foliage to be certain that it’s healthy and hydrated.
(Sources: sfgate.com and wikihow.com)
