Spring is an ideal time to refresh mulch in your landscape. To maintain a neat, well-kept appearance, landscape beds and tree rings can be edged and topped with a fresh layer of mulch. Areas that receive full sun typically require more frequent mulching, as heat accelerates decomposition compared to shaded, north-facing beds.
Be careful not to overapply mulch. Excess mulch can retain too much moisture, leading to disease and root rot. Ideally, a 2-inch layer provides a clean look while helping to prevent weed seeds from germinating. In many cases, a thin top-dressing is all that’s needed to maintain this depth.
If weed seeds are a persistent issue, a pre-emergent weed control can help prevent germination. However, use caution if you plan to seed grass, as pre-emergents will also prevent grass seed from growing. Existing weeds must be removed before applying mulch, as pre-emergents do not control established weeds. A properly maintained mulch bed alone will prevent most weed growth.
There are many mulch options available, including pine bark, shredded or processed wood mulch, and dyed mulch. Leaf compost mulch is especially beneficial in perennial gardens because of its high organic content, which improves soil health. Organic mulches help retain moisture, regulate soil temperature, and create an ideal environment for root growth.
One of the best uses for mulch is expanding tree rings around evergreens to allow for their natural growth. Trees like Colorado blue spruce and junipers often outgrow their original rings, and lawn mowing can damage their shape over time. Expanding the ring by 18–24 inches is usually sufficient. Mark the new edge using spray paint or a garden hose, remove the sod, and apply 2–3 inches of fresh mulch. This not only improves appearance but also promotes healthier growth.
Colorado blue spruces, in particular, have shallow root systems and are sensitive to drought. Extended dry periods can damage roots quickly. Mulch helps retain soil moisture, but supplemental watering may still be necessary. Soaker hoses with timers are an effective, low-cost solution. Just remember, overwatering combined with excessive mulch can harm plants.
To check if you have the right amount of mulch, pull it back from the base of trees—you should be able to see the root flare. If the trunk goes straight into the ground like a telephone pole, there is likely too much mulch. “Mulch volcanoes” trap moisture against the bark, encouraging root girdling and eventual tree decline. Rake mulch away from the trunk and allow existing mulch to decompose before adding more.
While mulching can be done almost any time of year, spring is especially beneficial. Don’t overlook fall mulching either—adding mulch before winter improves appearance and helps protect plants during colder months, especially as winters bring less consistent snow cover.
