CORVALLIS, Ore. — Many homeowners who want less yard work are replacing lawn with mulch and other low-maintenance landscaping.
“The coarser the better,” said Al Shay, instructor in the Oregon State University Department of Horticulture.
Organic mulches help conserve water, reduce weeds, improve soil quality and protect plant roots. Wood chips shade the soil so weed seeds are less likely to sprout and they take a long time to break down. Shay recommends chips from hardwood tree species such as oak or maple and suggests using wood chips instead of bark dust.
How to apply it
Weed and water the bare ground where you will apply mulch. If you want extra weed control, lay down one layer of cardboard or landscape fabric before mulching. Spread 2-3 inches of wood chips over the soil. Local arborists and lumber mills are good sources for chips.
“Wood chips are readily available and this keeps them out of the waste stream,” Shay said. “You can minimize the time spent on managing weeds and add organic detritus to the soil. It’s a low-maintenance, sustainable approach that makes sense.”
When to mulch in Oregon
Oregon’s wet west and drier east handle mulch on slightly different calendars, but spring and fall are the sweet spots.
- Western Oregon — Willamette Valley, Portland area, Oregon Coast: late March through May or September through October. Spring soils are workable and spring rain helps settle the mulch. Fall works well because summer weeds are slowing and fall rain finishes the job. Skip midwinter when soils are saturated to avoid compaction.
- Central and Eastern Oregon or higher, drier elevations: late April through June or September, before hard freezes. Wait until the ground is thawed but not dusty dry. Fall is good, but do not push too close to the first strong cold snap.
If you plan to sheet mulch — cardboard with mulch on top — try to time it with fall rain in Western Oregon so nature does the watering.
Other good options
- Leaves
- River rock
- Mint compost
- Hazelnut shells
Mint compost is made from peppermint hay and the distillation process that extracts peppermint oil also kills weed seeds. Hazelnut shells, available in Western Oregon from local orchards and some nurseries and soil suppliers, look good on paths and tend to stay put; they may be harder to find in Eastern Oregon.
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