Creating a resilient landscape with arborist wood chip mulch
Horticulture & Turfgrass
Linda Chalker-Scott
Extension Specialist and Professor
Washington State University
Puyallup
Abstract
The current trajectory of climate change suggests that summer temperatures will rise, and drought conditions worsen, in many parts of the world. A well-chosen mulch can reduce soil water loss in gardens and landscapes and preserve landscape plant health. Not all mulches are created equal, however, and some mulches can damage both soil and plant health. Poor mulch choices include
- sheet mulches, such as cardboard, newspaper, landscape fabric, and plastic
- hydrophobic mulches, including many bark mulches, nutshells, and pine needles
- synthetic mulches like rubber mulch
This presentation will review the scientific literature on arborist wood chip mulch – arguably the most beneficial landscape mulch available to homeowners. However, many misconceptions about arborist chip mulches exist, including:
- negative impacts on soil chemistry, including nitrogen levels and pH
- plant pathogens on diseased wood
- flammability
- attractiveness to pests
We will present the science-based evidence supporting the use of wood chip mulches, including
- improved soil health
- sustainable addition of plant nutrients
- support of roots and mycorrhizae
- weed suppression
- enhanced plant establishment and survival
The information in this presentation will provide extension agents and Master Gardeners with practical, science-based information to assist them in advising home gardeners and other clients in improving the resiliency of their landscapes.
Authors: Linda Chalker-Scott, A. J. Downer
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Linda Chalker-Scott Extension Specialist and Professor, Washington State University, Washington, 98371
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A. J. Downer Farm Advisor, University of California, California, 93003