Landscape mounds and berms are a great way to add interest to your yard and landscape. They’re straight forward to build if you follow these simple design guidelines.
What is a Berm?
Berms are raised mounds of soil, dirt or buried material. Berms adorned with appropriate shrubs, trees or flowers, are used for a variety of purposes including providing seclusion, acting as a moderate wind break, gathering light and shade for plants to thrive, such as flowers or vegetation with striking colours like reds or purples. They can also block and redirect foot traffic. They can add aesthetic value when displaying other items such as sculptures and large natural stones that are visually appealing from a variety angles.
Berms are commonly used to improve water drainage, and they also prevent water from pooling where they are located. Berms can help define a property’s boundary or can also be more centrally located for aesthetics.
Here a few photos that we like.
VIDEO – How to Make a Berm or Landscape Mound
Landscape Mounds and Berms Design
A landscape designer should plan the design of a mound or berm before constructing it. You can also create a design for yourself. Always consider the overall purpose of the mound as well as the drainage patterns in your landscape in advance. A spill containment berm could be one of the “purposes.” A garden berm or mound should be four to five times longer than it is tall, gradually flowing out into the surrounding landscape.
The majority of landscape berms are 18-24 inches tall. The design can have multiple peaks to add interest as well as shape to serve its purpose. Most are given a curved or crescent-shaped shape, which is preferable and looks more natural.
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Build A Berm Or Landscape Mounds
Berms are often constructed using fills such as plant debris, sand, asphalt, soil, or rubble. Use the fill materials to fill the major part of the berm, forming its shape around it using the soil. Firmly tamp the fills to ensure compactness. The LandscapingNetwork has this Pro Tip:
When grading mounds near existing trees and shrubs, never alter the grade nor disturb soil within a tree’s drip line. Also be sure the berm will not interfere with water that has previously supported the life and health of the tree.
Items You’ll Need to Have
- Graph paper
- Landscaping spray paint
- Garden hoses
- Clay soil
- Fill dirt
- Boulders and flagstones (optional)
- Shredded bark mulch
- Various plants
Sketch The Design To Scale On A Graph Paper Beforehand
Having a sketch of the berm to scale will help you become aware of the area the berm will occupy so that you can know whether you have enough room to build it. Berms meant to showcase trees should take a horizontal slope of 5-7 feet with 1-foot height from the base while those meant to showcase small plants can do well on a steep slope of 3-4 feet in length with a height of 1 foot.
The peak should be designed to occupy one end instead of taking the center position. Also, the top of the berm should be flat to prevent water run off to the sides of the slope. Be creative with the design, such that your berm has multiple peaks, undulant conical edges, or even crescent shape, rather than the perfect oval design.
Where Will Rain Go?
Water drainage is a key consideration in planning your berm. Ask yourself the question, “In a big rain storm, where will the water go?”
Put Down Your Layout Plan
Lay out the berm design on the ground using the garden hose; garden hoses are preferred because they flex easily to achieve perfect curves to layout an island bed and also offer flexibility in the design. After you’re content with the shape, transfer it to the lawn using a landscaping spray paint.
Remove The Turf Layer In The Marked Lawn
Use your spade to remove the turf clutter so that the marked turf is now ready for refilling. Curve it with grass, if possible, so that you can be able to see your design as you fill it up with dirt.
Fill The Area With Clean Dirt To Build Up The Berm
Use a garden hose to spray the mound so as to moisten the soil and then tamp it tightly. The fill dirt should take up about half of the total height of your berm. The remaining part should be filled with top soil.
Fill The Remaining Few Inches With Clay Soil
Depending on the height, cover up the fill dirt with 1 foot of clay soil. Any other correction in the berm design should be made using clay soil. Clay soil is preferred as it compresses well and it’s not likely to be eroded by runoff water.
Add Top Soil Over The Clay Layer
Bulk up the remaining height of your berm using topsoil; this will provide nutrients for your vegetation.
Use A Shovel To Flatten The Top Soil For A Good Shape
Drag the topsoil using a bow rake down to the outlines of the berm to achieve significant slope and smooth edges. Compress the top soil especially on the sides of the hill to ensure that it’s compact.
Naturalize Your Berm
Place large boulders and flagstones throughout the berm to give it a more natural outlook. Bury one-third of the stone height to hold them firmly in the soil, and also to make them appear as natural features on the hill.
Plant the vegetation of your choice be it trees, perennial and annual flowers, groundcovers and shrubs on the berm so that they can establish roots to anchor the soil, especially on the sides of the slope.
Short plants should be planted at the peak of your berm; this will make them more visible. You can have several trees at the top of your berm as well, but plant them in an irregular pattern so that they can look natural.
Plant the groundcovers at the slope of your berm to help preserve the soil from being eroded.
Add a 2-3 inches film of mulch around the plants; use mulches with uneven shapes to prevent erosion. Shredded barks can make good mulch as they interlock to resist washing down the slope.
The Bottom Line
There are no specific rules for building a berm. The landscape outlines will dictate the design as the rest lies with the owner’s needs and preferences. Be creative and unique.
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