Yard and Garden: Mulch insulates soil for winter temperatures

By Tom Dominguez

The single most timesaving practice for any gardener is using mulch around garden plants. Mulching goes hand in hand with planting – in fall or any other time of the year. You can buy various types of mulch or use leaves (chopped, shredded, or composted) or other garden material you already have.

Mulch performs several functions. A layer of mulch at least 3 inches thick produces a barrier to weeds; most weed seeds in the ground do not have enough light and air to grow through the mulch. In addition, the ground is protected from weed seeds dropped by birds or animals.

An organic mulch, such as bark nuggets, shredded bark or wood, chopped leaves, pine needles, leaf mold (composted leaves), or cocoa hulls, conserves water. Water the plant and surrounding soil well, add the mulch, and then water again. Take care to keep the mulch an inch from the plant stem or you risk suffocating it. The mulch prevents moisture evaporation from the ground, especially in the heat of summer. Using organic mulch has an added bonus; as the mulch decomposes, nutrients enrich the soil.

Mulching is even more important at this time of year as the weather changes and the temperatures drop. A three- to six-inch layer of organic mulch helps maintain soil temperature. In areas where the ground freezes. Lack of winter mulch leads to the death of many perennials and small shrubs as the roots are exposed to freezing air and the plant dies.

In cold-winter regions, wait to add winter mulch until the ground has frozen. If you mulch too early in fall, the mulch will keep the soil at above-freezing temperatures and encourage the plant to keep growing. Unfortunately, the tender new growth is susceptible to the cold air temperature and is likely to be killed. Normally, as the temperatures fall, plants go into dormancy, which prevents most dieback.

Even though they are not visible in fall, most spring-blooming bulbs benefit from a good winter mulch, as do hardy perennials that have died back to the ground. Hybrid tea and grandiflora roses need a good mulching to make it through sub-freezing winters. Make a note to begin removing the mulch in late winter to early spring as days start to warm; you don’t want to miss any of the spectacular early show of color that begins with small bulbs and woodland perennials and continues through spring and into summer.

Organic gardeners will want to make sure that mulches they purchase do not contain recycled wood with CCA (chromated copper arsenate, an arsenic-based pesticide that’s registered and controlled by the EPA).

Bags of mulch with the Mulch & Soil Council (MSC) certification logo will identify the ingredients of the mulch. MSC certified mulch is available at many major nurseries and garden centers. Home Depot stores were the first to require mulch suppliers to certify their products.

More winter plant tips:
• Prolong the life of holiday-season gift plants by providing proper care.
Check to see if the pot wrap has plugged up the bottom drainage. Don’t overwater. Keep out of drafts from heating vents and opening doorways.

Fertilizer is seldom needed the first few months.

• Take advantage of good weather to prepare garden beds for spring planting. Work in any needed organic matter, and have beds ready to plant when needed.

• Don’t forget tulip and hyacinth bulbs in the refrigerator. They can be planted any time in December if they have received 60 or more days of chilling.

• Want to start cuttings of your favorite Christmas cactus? As soon as it has finished blooming, select a cutting with 4 or 5 joints, break or cut it off, and insert the basal end into a pot of moderately moist soil.

Place it on a window sill or other brightly lit area. The cuttings should be rooted within 3 to 4 weeks.

• Don’t spare the pruning shears when transplanting bare-rooted woody plants. Cut the tops back at least one-third to one-half, to compensate for the roots lost when digging the plant.

• Berrying plants, such as holly and yaupon, may be pruned now while they can be enjoyed as cut material inside the house.

Tom Dominguez is an agent with the Quay County Extension, NMSU Extension Service. He can be reached by emailing todomingu@nmsu.edu or by calling 461-0562.