April usually starts out yucky in our neck of the woods. It’s brown and messy and we’re impatient to cover up the wet decay with something fresh, and nothing beats the smell and tidy look of a new layer of bark mulch, right? Well, I’ve been reading about that and talking with other pros in the industry and if you’re a traditional gardener attached to the tidy mulch aesthetic you may not like what I have to say. The advances of ecological research are making it quite clear that plant-community based design is the way of the future resulting in healthier plants, and a drastic reduction in resources – less time weeding, less money spent on mulch. The writing on the wall says we will be abandoning our mulching practice as we know it and replacing it with living green mulch – lots of vertical plant layers including a dense ground cover layer.
Bark mulch belongs under trees and woody shrubs, sprinkled between the ground cover if it’s too dark to allow vigorous plantings, and that’s about it. Here’s why. If you look at your landscape as a reproduction of very simplified natural plant communities you end up with three archetypes including meadows, woodlands, and the intersection of the two which is called Savannah, or the woodland border. The meadow contains herbaceous annuals and perennials, naturally crowded so tightly together that there is no exposed soil, and it dies back each year and leaves behind bacteria rich, high nitrogen, rapidly decomposing organic matter. In other words a meadow creates and feeds itself compost. The woodland contains trees that shed leaves and woody material that break down slowly thanks to fungi, and thus recycles its own energy in the form of something similar to a combo of leaf mold and bark mulch.