Should we irrigate in the winter?
by Curtis Smith, PhD, NMSU Extension Specialist
Q. We are having a debate regarding the need for irrigation of trees and shrubs in the winter versus the risks of having a garden hose attached to the outdoor faucet. Should we irrigate in the winter?
Kay S.
Albuquerque
A. Trees and shrubs (and dormant herbaceous plants such as bulbs, peonies, etc.) need water during the winter. These plants are still alive and living organisms requires water. Deciduous trees and shrubs, dormant herbaceous ornamentals, and many other plants need much less water during the winter than during the growing season because their metabolism is slowed and because water loss is less under conditions of winter temperatures. Evergreen trees and shrubs are also using less water than in the summer, but their water requirements are higher than those of the deciduous plants. In general, one good irrigation every 4 weeks during the winter is adequate to sustain most trees and shrubs. If the plants are growing in a clay soil (which holds greater quantities of water) irrigation may be somewhat less frequent (once every 5 to 6 weeks). Sandy soils will hold less water, so they need to be watered once every 4 weeks. Some plants, especially plants native to the lower elevations in our arid environment can tolerate very infrequent irrigation, but even these plants may exhibits some symptoms of injury after a very dry winter. However, many of our landscape plants are native to regions with higher levels of moisture in the winter and will be injured by winter drought. (continued at SW Yard and Garden column, December 19, 2009)
