During heavy storms and strong winds, some types of mulch have a hard time staying put. When we bought our house, it came with fresh pine bark mulch, and after the first storm I found mulch scattered 25 feet out into the yard!
When that happens, mowing becomes difficult and dangerous, your sidewalks and driveways look messy, and your planting beds soon sprout weeds.
After putting all that work into spreading mulch in your garden, the last thing you want to do is spend time raking it back in after every rainstorm! Here are some tips for keeping mulch in your planting beds where it belongs.
Choose the Right Mulch
All mulches will float and wash away in a flood, but some are more likely to stray than others. Here are the common types of mulch and their floatability factor:
- Chips and Nuggets: Wood chips and bark nuggets are infamous for floating away in heavy rain. If you go this route, get larger nuggets that will be heavier.
- Shredded Bark or Wood: Shredded mulch is a good choice because the pieces tangle and hold each other down. Look for medium or coarse ground mulch with a mixture of large and soft pieces. Hardwood mulches are heavier – and stay in place – better than softwood (pine) mulch.
- Pine Straw: Pine straw is my favorite choice because the needles entwine and help it stay put. For this reason pine straw is often used on slopes.
Remove Landscape Fabric and Plastic Sheeting
If your garden is on a slope or has a tendency to wash out, avoid putting landscape fabric or plastic sheeting underneath your mulch. These create a nice slick surface for the mulch to slide right out of the bed. Instead, to keep weeds at bay, apply multiple thin layers of mulch, watering each layer to help pack it down.
Edging the Beds
The only way to keep mulch completely in the flower bed or garden is to edge it with something high enough to hold in the mulch in place during a storm. Some ideas include:
- Landscape Edging: Wood, metal, plastic, or stone edging can help keep mulch in its place. Make sure the edging is several inches high.
- Plants: Edging plants make a great border to hold in mulch. Monkey Grass (Liriope sp.), Hostas, and ground covers are great choices if planted closely together along the edge of the bed.
- Pine Straw Edging: Gardeners who love their bark or chip mulch may have success by edging the beds with a foot-wide row of pine straw to catch floating nuggets.
- Trenching: A small trench (3-4” deep) around the edge of the flower bed can catch washed-out mulch before it gets into your grass. It’s easy to then rake it from the trench back into the bed.
- Edging with Mulch: You can also try piling your mulch deeper around the edges of the bed to form a low barrier that may keep it from washing as much.
Help for Slopes
On steep slopes, you’re going to need to take additional measures if you want mulch to stay where you put it.
Ideally, steep slopes should be terraced to create smaller, flatter areas that will hold soil and mulch in place. Terraces help create more garden space, too.
Another option is to cover the mulch with bird netting, then use landscape fabric staples to hold the netting in place and keep the mulch from sliding downhill.