Anonymous
I have to do it annually. We have too much wash away because of a sloped yard that goes into a creek. Costs a fortune, but I don't know what else to do.
Use pine needle mulch. They sell it in bales at nurseries. The needles interlock and will not wash down a slope.
If you have new beds, mulch twice a year for the first year or two. With new plantings you have a lot of seeds in the soil(seed load) that will grow all through the season and in to the fall. Established beds just need spring mulching and weeding. In the fall the growing season is over. So everything slows down...include the growth of weeds and the break down of the mulch.