• Pay Bill
  • Customer Support
  • Contact
  • Emergencies
  • Español

A Guide to Tree Care in Dry Climates

Tips on Tree Watering from the Colorado Tree Coalition

Sometimes your trees could use a drink. Prolonged dry periods and high winds can dry trees and soil. Watering your trees will help ensure their optimum health.

The boxed area is the drip line, or critical root zone.

Tree roots are not like carrots

Tree root systems can spread two to four times wider than the height of the tree. Most of the tree's absorbing roots are in the top 12 inches of soil.

Water should be applied within the drip line (the critical root zone shown at left).

Water deeply and slowly

Apply water so it moistens the soil in the critical root zone to a depth of 12 inches. Water with a deep root fork, soaker hose, five-gallon bucket or soft spray wand. Apply water to many locations under the drip line. If you use a deep root fork or needle, insert the device no deeper than eight inches into the soil.

How much water to apply

April through September: In normal precipitation years, trees located in irrigated turf areas do not need additional water.

When watering restrictions prohibit turf watering, or when trees are not in turf areas, water small trees four times per month, medium trees three times per month and large trees two times per month.

October through April: During prolonged dry periods, water once or twice a month, using 10 gallons of water for each inch of the tree’s diameter. Water only when the temperature is above 40 degrees and there is no snow on the ground.

Mulch helps retain soil moisture

Mulch helps conserve soil moisture. Apply organic mulch within the drip line, at a depth of three to four inches. It is best to eliminate turf prior to adding mulch. Leave a six-inch space between the mulch and the tree trunk. Mulch materials may include wood chips, bark, leaves and evergreen needles.

Moisture is needed to avoid disease

Maintaining consistent soil moisture allows for better water absorption. Stressed trees are more vulnerable to disease, insect infestations and branch dieback.

The Colorado Tree Coalition has more advice about tree health from professional foresters, arborists and water conservation specialists.


  • Summer watering schedule (April – September)
    April – September Tree Watering Schedule
    (Minimum Water Requirements)
      Small Trees Medium Trees Large Trees
      Weekly (10 gallons/inch)
    Three times a month (10 gallons/inch)
    Two times a month (15 gallons/inch)
    Trunk size in diameter (inches) 1" 2" 3" 4" 6" 8" 10" 12" 14"
     Watering Device
     

    Deep root needle 2 gal/min

    Deep root needle
    2 gal/min

    5
    min
    10
    min
    15 min 20
    min
    30
    min
    40
    min
    75
    min
    90
    min
    105
    min

    Hand_wand2

    Soft spray wand
    4 gal/min

    3
    min
    5
    min
    8 min 10
    min
    15
    min
    20
    min
    38
    min
    45
    min
    53
    min

    Soaker_hose2

    Soaker hose
    2 gal/min (50 feet with restrictor)

    5
    min
    10
    min
    15 min 20
    min
    30
    min
    40
    min
    75
    min
    90
    min
    105
    min
  • Winter watering (October – March)
    October – March Tree Watering Schedule*
    (Minimum Water Requirements)
      Small Trees Medium Trees Large Trees
      Weekly (10 gallons/inch) Three times a month (10 gallons/inch) Two times a month (15 gallons/inch)
    Trunk size in diameter (inches) 1" 2" 3" 4" 6" 8" 10" 12" 14"
     Watering Device
     

    Deep root needle 2 gal/min

    Deep root needle 2 gal/min

    5
    min
    10
    min
    15
    min
    20
    min
    30
    min
    40
    min
    50
    min
    60
    min
    70
    min

    Soft spray wand 4 gal/min

    Soft spray wand 4 gal/min

    3
    min
    5
    min
    8
    min
    10
    min
    15
    min
    20
    min
    25
    min
    30
    min
    35
    min

    Soaker hose 2 gal/min

    Soaker hose
    2 gal/min

    5
    min
    10
    min
    15
    min
    20
    min
    30
    min
    40
    min
    50
    min
    60
    min
    70
    min

    * Water only when the temperature is above 40 degrees and there is no snow on the ground.

Visit saver.denverwater.org for more suggestions on tree and shrub care in our dry climate. The website offers tips from tree care professionals on the following subjects:

  • General tree watering recommendations
  • Tree watering devices 
  • Caring for trees 
  • Planting trees and shrubs 
  • Shrub watering recommendations