How to Keep Mulch From Floating Out of Flower Beds

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. The key to keeping mulch in place is choosing the right type, proper installation, and using effective retention techniques

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.
• Physical barriers: You can use landscape rocks, pavers, bricks, etc. to create a barrier for your mulch

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. DIY 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. I recommend gorilla hair mulch on slopes, too — it tends to stay in place better.

How Much Mulch is Too Much?

As a general rule, maintain a 2-3 inch layer of mulch in your beds. Avoid piling mulch against tree trunks, or plant stems, as this can lead to rot and pest problems.

Over-mulching can suffocate plant roots, prevent water from reaching the soil, and create a habitat for harmful insects. Plus, when you add too much mulch, you’ll risk the top layers of the mulched area washing away in the rain. Remember, when it comes to mulch, more isn’t always better.

Other Mulching Mistakes to Avoid

One common mistake is using the wrong type of mulch for your climate and garden needs. Avoid using lightweight mulches in windy areas or on slopes. Another error is not preparing the soil properly before mulching, which can lead to weed growth and poor plant health.

Failing to refresh your wood mulch annually can result in compacted, ineffective layers. Lastly, don’t forget to leave some space around plant stems and tree trunks to prevent moisture buildup and potential disease.

Here are some key mulching mistakes to avoid:

• Using the wrong type of mulch for your specific needs
• Applying mulch too thickly (more than 3-4 inches deep)
• Creating “mulch volcanoes” around trees
• Failing to remove weeds before mulching
• Not refreshing mulch beds annually
• Applying mulch right up against plant stems and tree trunks
• Using fresh wood chips or sawdust, which can rob soil of nitrogen
• Neglecting to water thoroughly after applying mulch
• Mixing mulch into the soil instead of leaving it on top
• Using dyed mulches in vegetable gardens or near edible plants

How to Level Your Garden Beds

Leveling your garden beds is crucial for proper water drainage and mulch retention. Start by removing any existing plants and clearing the area. Use a rake to rough-grade the soil, then lay a long, straight board across the bed to identify high and low spots.

Add or remove soil as needed to achieve a consistent grade. Aim for a slight slope away from structures to ensure proper drainage. Once level, compact the soil lightly with a lawn roller before replanting and applying mulch.

Final Thoughts

Keeping mulch from floating out of flower beds doesn’t have to be a constant battle. By choosing the right type of mulch, implementing proper edging techniques, and avoiding common mulching mistakes, you can create a stable, beautiful garden that withstands even the heaviest rains.

Remember to level your beds, use heavier mulch materials on slopes, and consider alternative ground covers like landscape rock beds in problem areas.