Landscaped berm with deciduous tree and conifer in a home garden
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Tips For Making Landscape Mounds And Berms

Landscape mounds and berms are an easy and attractive way to add interest to your yard and landscape especially those with flat areas. Building them isn’t as complicated as many would think. Simple design guidelines can avert potential landscaping troubles.

Landscape Mounds and Berms Design

Before building a mound or berm, a landscape designer should first plan its design. You can also design it for yourself. Always consider the mound’s overall purpose in advance as well as the drainage patterns within your landscape. One “purpose” could be a spill containment berm. On average a garden berm or mound should be about four to five times longer than its height, progressively streaming out into the remaining landscape.

Most landscape berms have a height of 18-24 inches. The design can have more than one peak to give it an added interest as well as shape to perform its purpose. Most are given a curved or crescent-looking shape, which is preferable and natural looking.
Related Reading: 37 Landscape Edging Ideas

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
  • Spade
  • Shovel
  • Clay soil
  • Fill dirt
  • Topsoil
  • 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

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.

Vegetation

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 Mulch

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.

VIDEO – Berm Building Video to Wrap Up

The voice on this video seems computer generated. If you can get through the voice, the points support many of those above.

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