Mulch wash out is pretty common this time of year.  Frequent and strong spring rains can do a number on your mulch beds.  Most mulch wash out is caused by installing the mulch products in less than ideal areas.  Common problem areas include hills, low areas and areas in direct contact with down spouts.  Since mulch is a wood bi-product, it will float when exposed to significant water accumulations.  Mulch wash out is more common with bark products because they are lighter than hardwood products.  Being proactive and using mulch in the correct application will significantly reduce your chances of mulch wash out.

Mulch Wash Out

How to avoid mulch wash out.

Choose a mulch products that is consistent in size and hard wood.  Most mulch will be shredded down to two-inch pieces and smaller.  Cleaner and consistent products will tend to stay in place better than finer mulch products.

Avoid using mulch products on steep hills.  Any time you install mulch products on steep hills, you are asking for wash out.  Gravity in conjunction with heavy rains will wash your mulch right away.  If it is possible, consider grading your application area prior to installing mulch.  If you reduce the steepness of the application area, you will have better results.

Install a bubbler box on the end of your down spout.  This will reduce the force of the water coming from your down spouts.  Bubbler boxes can be installed outside of the landscape bed to encourage the water to flow away.

Landscape rock will survive longer in run off areas over mulch products.  The larger the rock, the better chance you have of it remaining in place.

Use mulch in the appropriate application such as around tree bases and flower beds.  If you over install your mulch products in these areas, you will increase the chances of mulch floating away.  It is important to only top-dress it is required.  If you have ample mulch and want to freshen it up, consider re-dying the mulch instead of re-applying it.