Watering trees in Arizona's arid climate requires careful attention to ensure their health and longevity. Here are some practical tips:
1. Understand Tree Watering Needs
- Young Trees: Newly planted trees need more frequent watering (every 2-3 days initially, tapering to once a week after a few months).
- Established Trees: Mature trees can thrive with deep watering every 2-4 weeks, depending on the season.
2. Water Deeply and Infrequently
- Focus on deep watering to encourage deep root growth. Water should penetrate 2-3 feet into the soil, which is where most tree roots grow.
- Avoid shallow, frequent watering, as it promotes surface roots that are more vulnerable to heat and drought.
3. Water at the Drip Line
- The “drip line” is the outer edge of the tree canopy. Water here rather than near the trunk to target the area where feeder roots absorb water most effectively.
4. Water Early in the Morning or Late Evening
- Watering during cooler times of the day reduces evaporation and ensures more water reaches the roots.
5. Adjust for Seasons
- Summer (May–September): Water more frequently, but still deeply.
- Winter (October–April): Reduce watering frequency, as trees are less active during cooler months.
6. Monitor Soil Moisture
- Check soil moisture 12-24 inches deep using a soil probe or screwdriver. If it’s dry at that depth, it’s time to water.
7. Use Mulch
- Apply a 2-4 inch layer of mulch around the base of the tree (but not touching the trunk) to retain soil moisture and reduce temperature fluctuations.
8. Use Efficient Irrigation Methods
- Drip irrigation or soaker hoses are ideal for slow, deep watering.
- If using a garden hose, let it run slowly to ensure deep penetration without runoff.
9. Choose Native or Drought-Resistant Trees
- Native or desert-adapted trees like Palo Verde, Mesquite, or Ironwood require less water once established.
10. Look for Signs of Overwatering or Underwatering
- Overwatering: Yellowing leaves, standing water, or soggy soil.
- Underwatering: Wilting, browning leaves, or dry, cracked soil.