By: MEGHAN SHINN
https://www.hortmag.com/smart-gardening/mulching-trees-shrubs
Spring might find you planting new trees and shrubs in your garden and landscape and providing some routine care to the woody plants that are already growing there. Both of these tasks usually involve the application of mulch. Here are some tips to remember when adding mulch to new or existing tree and shrub plantings:
For existing plantings, add only as much mulch as it will take to increase the overall depth to about three inches for coarse mulching materials (such as bark chips) and two inches for fine materials (such as shredded bark). For instance, if the material applied in previous years has deteriorated to a depth of about an inch, you need only add a top layer of two inches.
Try to apply mulch in mid-spring, after the soil has warmed up a bit and spurred roots to begin growth.
Avoid pressing mulch up against the stems of shrubs. Instead leave a couple of inches of bare soil ringing the stems.
Similarly, do not pile mulch up against the trunk of a tree. Bring the mulch to the base of the root flare (the swollen portion at the bottom of the trunk), but never cover it!
If possible, extend the mulch out so it ends under the drip line of the tree or shrub (the outer edge of the branches). If that’s not possible, try for a mulch ring with a minimum diameter of four feet.
