Drawback to Woodchips: They do attract vermin

Q. My backyard has several planting beds containing roses, rosemary, mock orange, euonymus, pyracantha, lantana, sago palms, and other plants. I added rock to the soil surface eight years ago and these plants started to decline in about five years. I decided to remove the rock and put woodchips down instead but afraid of roaches entering the house from the woodchips.

Irrigation valve box amongst plants receiving water. When you combine woodchips, water and a valve box it is normal for cockroaches and spiders to live and enter there. Spray the inside of these boxes with an insecticide once a year to help reduce these numbers. But this will not stop them from helping to decompose the woodhips.

A. Insects such as cockroaches like water and something to eat. They live in the woodchips exposed to water because they help break down debris from the wood chips. Cockroaches, unpleasant as they are, are decomposers. Their favorite place to congregate in the landscape is in irrigation boxes where it stays wet. They are attracted to these wet areas and warmth of your home when it gets cold so they may come inside as their populations get larger.

Keep landscape areas close to the home dry. Apply water to landscape plants no closer than 3 feet from your house exterior walls. There isn’t a good reason to apply water closer than this. In a desert climate where there is limited rainfall, plant roots follow irrigation water. Irrigating foundation plants on the side away from the home causes their roots to grow in that direction. Keeping the soil dry surrounding your home also reduces water damage to the cement as well as reducing insect problems inside the home.

After removing the rock and before you apply woodchips, sprinkle the wet areas around plants with a rich compost to help feed the plants, enrich the soil, and start the decomposition process.