What's the best way to care for a tree during a drought?

Depending on the species of tree and where it’s planted, trees may need some extra help during drought conditions.

Extended droughts can cause decline and death on both young and mature trees. Even large trees more than one hundred years old can decline. It’s better to apply water preventively before the tree canopy begins losing foliage than to wait until these symptoms are advanced.

  • Water is one of the most important things trees need. Trees take in water by their roots but many people water the leaves of their trees, creating an environment for disease. Instead, adjust sprinkler heads down to water the soil. Some sprinkler heads may need the nozzle changed to a flat spray.
  • Do not water near the trunk unless you’ve planted the tree within the last four or five years. Instead, water the area under the drip-line (edge of the branches) where the tree’s root system extends.
  • Water slowly, this allows water to adhere to soil particles on its way down. Soaker hoses and drip irrigation work well.
  • Residents in the City of Los Angeles are now prohibited from watering their lawns between 9 a.m. and 4 p.m., and watering is limited to 15 minutes a day. Residential DWP customers who violate the rules will be fined $100, which is double the old fine of $50 for a first-time offense. The fine for businesses that violate the rules quadrupled to $200. Repeat residential offenders can be fined up to $300 and commercial customers up to $600.
  • Mulch is a gardener’s best friend. A three to four inch layer of wood chips spread on bare ground will reduce water evaporation, insulate roots from heat, keep the weeds away, and give a home to beneficial microorganisms.
  • Avoid over-fertilizing your trees or you may find that sap-sucking insects such as aphids, white fly and scale are paying you a warm weather visit. Pest populations, including insects and disease, increase rapidly with warmer weather. Keep things in balance and you’ll reduce your problems.
  • Mature trees: We often take our large trees for granted and forget that they can decline in health during extended drought. Most people don’t realize the tree is in trouble because symptoms appear first in the top center portion of the canopy far from view.
  • Do not prune live branches in a severe drought. Removing live tissues forces the tree to expend energy to defend against the pruning cuts. Removing live foliage also reduces the capacity of the tree to grow once rains return.
  • Do not fertilize trees in extended drought since this pulls water from the roots and forces the tree to expend precious energy to process the fertilizer.
  • Do not dig under the canopy of the tree in drought. Digging under the tree kills the small roots that absorb water, thus reducing the tree's capacity to uptake water.