Watch out for Volcano Mulching! March is here and it will very soon be time to get started on all of those outdoor chores that have been saving themselves for us all winter. Cleaning up the leaves we left behind, dead heading perennials and cutting back all of those ornamental grasses and yes, Mulching all of our planting areas.
I am always amazed as I drive around town in the spring, to see that most of the mulch being applied to trees and shrubs is being done incorrectly. The reality is,too much mulch is being piled on top of the root systems, worse this process is being repeated season after season and sometimes more than once in a season.
Our landscapes are crying for help as we continue to suffocate them to death. Mulching is not so much about aesthetics as it is about horticulture. Mulch is to be a benefit to plants not a death sentence.
A few simple guidelines should be followed to ensure a proper installation.
In general an assessment of how much mulch you have should be made. If you have a layer of an inch or so this should be cultivated for aeration and a light top dressing of an inch or less applied. Mulch should never be piled high upon the bark of a tree or over perennials as this only serves to rot perennials and bark and cause abnormal root growth above the root flare allowing girdling to take place. (Volcano Mulching) this is a very slow death but certain. Applied properly mulch will hold moisture and keep the ground around plants from drying out faster, suppress weed development and as it breaks down adds organic matter 
to your soil.
During new plant installations we will apply mulch over bare ground at about a two inch depth no more. The subsequent season may require a freshening up. For greater weed control a pre-emergent herbicide should be applied before the mulch is spread. Landscape fabric is often used and should be installed to allow ample room for plant growth and development. I prefer the plain hardwood bark mulches rather than the dyed, ground up wood products on the market today. These ground wood products tend to rob the soil over time of its nutrients instead of giving themselves back to the earth naturally like the bark mulches do.
As with most installations, moderation, good nutrition and horticulture, and the use of proper techniques will ensure a healthy and more vigorous landscape that will be aesthetically pleasing for many years.
Happy mulching!