A Leaf Out Of Our Book

Our Monthly Resource Column

Why Winter Water?

It's winter. We don't need to worry about our lawns and gardens, right? 
WRONG! In the high and dry conditions of Colorado,  winter watering is essential! Our plants are losing water all the time to dessicating wind and are physically unable to absorb it in their dormant state from the parched soil. Many a tree and shrub looks terrible in June because its roots were destroyed by winter dessication in January. 

What To Do?

The Colorado Extension Office recommends following these guidelines: 

  •  Water only when air temperatures are above 40 degrees F.
  • Apply water at mid-day so it will have time to soak in before possible freezing at night.
  •  Water trees, shrubs, lawns, and perennials during prolonged dry fall and winter periods to prevent root damage that affects the health of the entire plant.
  • Water only when air and soil temperatures are above 40 degrees F with no snow cover.
  • Established large trees have a root spread equal to or greater than the height of the tree. Apply water to the most critical part of the root zone within the dripline.
  • Apply 10 gallons water for each diameter inch of the tree. For example, a two-inch diameter tree needs 20 gallons per watering. Use a ruler to measure your tree’s diameter at 6" above ground level.
  • In dry winters, all shrubs benefit from winter watering from October through March. Apply 5 gallons two times per month for a newly planted shrub. Small established shrubs (less than 3 feet tall) should receive 5 gallons monthly. Large established shrubs (more than 6 feet) require 18 gallons on a monthly basis.
  • A solid layer (persisting for more than a month) of ice on lawns can cause suffocation or result in matting of the grass. Plants receiving reflected heat from buildings, walls and fences are more vulnerable to damage. The low angle of winter sun makes this more likely on south or west exposures. Provide these sites extra moisture.
  • Windy sites result in faster drying of sod and plants and require additional water.
  • Lawns in warm exposures are prone to late winter mite damage. Water is the best treatment to prevent turf injury.
  • Monitor weather conditions and water during extended dry periods without snow cover – one to two times per month.
  • Newly planted trees are most susceptible to winter drought injury. Trees generally take one year to establish for each inch of trunk diameter. For example, a two inch diameter (caliper) tree takes a minimum of two years to establish under normal conditions.
  • Trees obtain water best when it is allowed to soak into the soil slowly to a depth of 12 inches. Methods of watering trees include: sprinklers, deep-root fork or needle, soaker hose or soft spray wand.
  • Apply water to many locations under the dripline and beyond if possible. If using a deep-root fork or needle, insert no deeper than 8 inches into the soil.
  • Herbaceous perennial establishment periods vary. Bare root plants require longer to establish than container plants. Perennials transplanted late in the fall will not establish as quickly as those planted in spring.