What Is Floating Mulch?

Features

• Mulches promote plant health and simplify landscape maintenance. A layer of mulch applied as part of the open landscape design or around plants keeps soil temperature moderate, provides eye appeal and conserves water. Inorganic mulches include materials such as rock, rubber mulch, plastic sheeting and landscape fabric. Benefits of inorganic mulches include permanent or semi-permanent mulch. Organic mulches include materials such as grass clippings, pine straw, wood chips and bark pieces. Benefits of organic mulches include nutrient decomposition and easy application.

Floating Mulches

• While rocks or rubber mulch remain in place during most water activity, other inorganic mulch materials are not as stable. When water gets under plastic sheeting, it lifts the sheeting unless the plastic is anchored in place and weighted with rocks or wood mulch topping. Landscape fabric is porous and allows some water penetration but drifts out of place with water flow unless fabric staples or anchors hold it to the ground. Organic mulches like lightweight wood chips or cedar bark float easily on water and wash away from the prepared landscape.

Problems

• Floating mulches can create environmental and landscape problems. Plastic sheeting and landscape fabric do not decay quickly. Drifting on water runoff, these materials clog storm drains and sewers. They block street gutters, causing flooding and road hazards. When organic lightweight wood chips and cedar bark float away, they cause sidewalk and traffic hazards as well as creating cleanup problems. Loose mulches accumulate in irrigation drains and around buildings or bushes. These unwelcome deposits must be removed so that irrigation water or rainfall drain freely.

Prevention

• Landscape containment minimizes floating mulch problems. Use landscape anchors to affix inorganic landscape fabric or plastic sheeting to the ground. Rocks or wood mulch over the plastic minimizes floatation. When practical, create a mulching bed slightly lower than the surrounding grass or landscape so that the mulch is contained. It may float but quickly settles back in place when the water drains. Use landscape borders, mow strips or edging for mulch containment. When practical, choose hardwood mulches or shredded tree and brush mulch that resist water erosion. Grass clippings also decompose quickly and are not prone to drift.

Considerations

• For slopes or hillsides, use living vegetation such as plant groundcover for mulch. The plant roots help hold soil in place and disperse water flow. Avoid mulching over-wet soils. The mulch impedes water evaporation and encourages root rot or other fungus disease. Use organic mulches in wet climates since they can be raked away more easily than rocks or fabric when needed.