It is my understanding that mulching the garden/landscape beds can be a confusing process. I am often asked about how to properly mulch a bed and what type of mulch one should use. How often do you re-apply? How deep should it be? Here I will debunk a few mulch myths and explain how to use them properly, as well as a few things to avoid.
What type of mulch should I use?
Good question. Not all mulches are created equal. First of all it depends on what type of planting area you are mulching. If you are looking to mulch around the house in a foundation planting you should be using something that lasts a few seasons. Coarse mulches will last the longest – Pine nuggets or shredded cypress both take a few seasons to break down. You will only need to add a tiny amount to keep your beds looking fresh each year. We suggest raking your mulch to “fluff it up” before you apply new mulch. You may find that by turning it you have freshened the color and you might not need to add any more.
If you are mulching a perennial or vegetable area you should use a shredded mulch such as hardwood, shredded Pine, Hemlock, etc. Finely shredded mulches break down in one season, and as they break down they add compost directly to the garden. These types of mulch should be tilled into the soil or raked around and a new layer added each season.
Photo credit: ninefootone via Visual hunt / CC BY-NC-ND
How deep should my mulch be?
Excellent question. Never any more than 3”. You DO NOT need any more than that. If mulch is too deep it will retain too much moisture creating a perfect environment for insects and fungus. Also, water from rain or irrigation cannot reach the roots of the plant so it may dry out. You may be thinking “if it’s deeper I will have less weeds” – NOT TRUE. There are other methods for beating weeds, the depth of your mulch is NOT the way to accomplish this. Keep it 3” or less or you will be choking your plants.
Photo credit: eXtension.org: Gardens, Lawns, and Landscapes via Visual Hunt / CC BY-NC-SA
Avoid the volcano at all costs!
Volcano mulching is a big landscaping no-no. We see it all the time. I have included a handy diagram so you understand what you should NOT be doing. Heaping mulch around the base of your shrubs and perennials is bad for a couple of different reasons. First is that by piling it up you are choking the plant. This will cause the shrub or tree to create “girdling” roots that encircle the trunk and choke it. This leads to certain death. Secondly, in summer when mulch gets wet and the sun comes out it gets HOT. It will burn shrubs and perennials pretty quickly. Again…keep mulch to 3” and don’t let it touch the trunk or stem.
Join me next time where I will discuss methods for ridding your mulch beds of weeds.