Landscape Answers: Plants can need water in winter

Q: I've noticed that many of my evergreen shrubs – mostly junipers and boxwoods – are starting to look off-color, sort of brownish or light green. Should I be worried?

A: An off-cast color can be an evergreen plant's response to cold temperatures and chilling winds. The effect is common during heartland winters, but it tends to be mild and not very long-lasting. We don't see actual foliage loss or twig dieback except during unusually cold weather.

But, off-color also can result from dry conditions. Evergreens provide the most obvious clues of winter drought in the landscape because they retain their leaves year-round. In turn, they use and lose more water during winter than the deciduous plants do.

Although evergreens are at greatest risk during cold-weather dry spells, other plants that are likely to suffer from a wintertime moisture shortage include new lawns established the previous fall and any trees or shrubs that are five or fewer years of age.

Fortunately, you can water landscape plants any time the air temperature is above freezing and the soil isn't so frozen that moisture can't soak in. A deep soaking is best, which can easily take several hours. If the temperature drops below freezing after that, however, no plants will be harmed.

Just be sure that your water carrying system is detached from its source, drained and stored again for winter when you're through. You won't need to water again until a long-bladed screwdriver or metal rod, pushed into the ground, stops before it reaches 4 to 6 inches deep. That kind of rod only stops when it reaches thirsty, thirsty soil.

-- Source: Dennis Patton, horticulturist, K-State Research and Extension