Let’s Talk Dirt!

By+Linda Difley

One of the most frequent questions I am asked is “Which is better in a landscaped bed? Mulch or stone?” As a long time gardener I have experimented with many different gardening practices and have developed a few opinions along the way. For most residential landscapes I prefer using mulch in the landscaped beds. Mulch is best known as a form of weed control but has other valuable properties. During the heat of summer, mulch keeps the roots shaded and cool, reducing the need for extensive watering. During the winter, mulch acts as an insulator keeping the roots “warmer” and then in the spring the same insulating properties help warm the soil. When mulch is applied properly there is no need for a weed barrier. However, it has been my experience that many week-end gardeners spread mulch too thin and weed suppression is compromised. Mulch should be applied at a depth of 3-4” on a new bed and should only need to be top-dressed (2”) annually. Weeds that do grow in mulch are generally very easy to remove- root and all.

On the other hand, some homeowners have suggested stone as a better alternative to mulch. Stone does have the advantage of not needing to be top dressed annually. There, in my opinion, the advantages end. Stone is very heavy to work with and more expensive than mulch. Additionally, a weed barrier fabric is needed to initially reduce weed growth and keep the stones from sinking into the soil. When stone gets hot the heat is reflected back to the plants just baking them and the gardener! Stone does not particularly have good insulating properties for either hot or cold. When weeds finally invade your beds (and they will) you will have to resort to spraying them to keep them under control.

Q: I didn’t get my lilac shrubs pruned after they bloomed and now they are overgrown. By June they will really be a mess. What should I do?

A: You are right to be cautious about pruning. Lilacs set their flower buds for the next year after they are finished blooming in the spring. Your best course of action would be to selectively hand prune the branches that are the most overgrown. You will lose some flowering but not all. Once the lilacs have finished blooming you can then reshape your plant to a more pleasing form.