How to apply mulch — and how much

If you’re ready to start applying mulch to your garden, here’s what you need to know to ensure you get the best possible use of your mulch:

• When you plant: Applying mulch right after planting something is easy. Use a shovel or scoop with a trowel. Spread the mulch over the rootzone area but not flush up against a plant’s base or main stem (which can smother it or invite pests or disease).
• Depth depends on the sort of plant. Annuals and perennials are fine with an inch or so of mulch; shrubs, roses, and trees need 3 or 4 inches or more.
• During the growing season: Add more mulch midway through the growing season or whenever you notice it’s depleted. You may have to get down on your knees or wriggle around a bit as you try to deliver it where it’s needed without harming the plant or its neighbors. Again, use less for smaller plants, more for bigger ones.
• In the fall or for winter protection: Depending on the severity of your winters and the amount of snow cover you expect (a blanket of snow can act as a protective mulch, actually), you want to cover an overwintering plant well. You can cut down perennials first and then practically bury them under several inches of mulch. You shouldn’t trim back shrubs and rosebushes at this time, but you don’t have to be as careful as you were with midsummer mulching because the plant is no longer growing actively. For freezing winters, 6 or more inches around the base of these is good.

These amounts are guidelines only. You have to tailor them to your climate, growing season, and specific plants.
To limit erosion, don’t excavate large areas that are on a slope without planting or at least mulching soon, especially during the spring, when rainy weather can cause washouts.