Gardeners often choose black mulch because it looks attractive in the landscape and blends in well with the soil. But mulch isn't just for decorative purposes--it provides essential services for plants. Black mulch helps plant roots retain water, keeps the soil warm when the temperature drops and cuts down on weed growth. And for a garden element that has so many benefits, it is quite easy to use and maintain.
Spread a 2- to 4-inch layer of black mulch evenly around the base of trees, using a rake. Spread the mulch out 1 1/2 times as wide as the area within the tree's drip line, but keep it far enough away from the trunk so that the base of the trunk and root crown are uncovered.
Spread a 2- to 3-inch layer of black mulch evenly over garden beds, using a trowel. Use your hands to scoop the black mulch 1 to 2 inches away from the bases of individual plants.
Water the mulch with 1 to 2 inches of water to anchor it.
Replenish the mulch as needed to keep its height consistent as it biodegrades.