January is one of our coldest months of the year. Overnight low temperatures routinely dip into the high twenties, and the daytime highs rarely go above sixty five degrees Fahrenheit (20°-65°F). Foggy mornings or rain is common. Most of our ornamental plants are in their maximum state of dormancy at this time of the year.
Plant Pest Control
Dormant oil applied to your trees and shrubs at this time will help to control many overwintering insects and diseases in your landscapes. Populations of adult aphids, mites, scale, mealybugs and whiteflies (and their eggs) will be controlled with a thorough spraying of a dormant oil. The addition of a lime Sulfur mixture or fixed copper to the oil will also help to control many overwintering diseases. Peaches and nectarines should receive a minimum of two dormant sprays for peach leaf curl control. Snails and slugs problems are usually low at this time of year because of the freezing nighttime temperatures however in protected areas and periods of unusually warm weather they can remain active all year.
New Year, New Plants
Select and plant your bare root trees, shrubs and vines this month. You can find large savings by purchasing your roses, fruit trees and berry vines in bare root. Selecting larger/older stock will reward you by bearing fruit one to two years earlier, or by blooming with larger, more plentiful flowers such as with roses. You can also purchase ball and burlap plants that are also available this time of year. These plants are typically ten to fifteen percent cheaper than container grown stock. Furthermore, ball and burlap plants are field grown and do not have the root bound problems of many container grown plants.
Prune your deciduous trees, shrubs and vines if you did not do so last month. This is the preferred month to prune roses. Prune roses as the buds begin swelling. Cut background covers such as Vinca major (and minor), Hypericum and Mexican evening primrose. Mowing these plants to three to six inches invigorates lateral spreading and increases the flowering this spring and next. Maple trees may bleed if pruned this month. Cut a few small twigs then wait about five minutes to see if they bleed. Wait until Summer to prune if you notice any bleeding.
Loving Your Lawn
Continue to pick up leaves to avoid Smothering the grass. Avoid walking on the lawn when it is frosted or saturated as it is easily damaged.