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Self-Help Tree Care

How much water does a tree need, and why?

By: Lacey Russell, PhD | June 14th, 2018

Your lawn and trees need a lot less water than you think. In fact, it's good to let your landscape dry out between irrigating. I know this seems counterintuitive when the goal is to maintain a lush and healthy yard. But, as in a natural forest, many trees we use today as landscape trees have adapted to heavy, but infrequent rains.

Our trees have large and extensive root systems that give them the ability to adsorb and store large amounts of water from the soil. What does this mean for homeowners? Water less frequently, but for a longer period of time—about one inch per week.

A tree health specialist can coach you in proper care for your yard's unique watering needs.

How much water does my lawn need?

Turf grass also appreciates infrequent, but deep watering. Watering your lawn lightly and frequently will actually weaken your grass by promoting a shallow root system and making it totally dependent on you for water!

The jobs of roots

Tree roots have two main jobs:

  1. The entire root systems acts to hold the tree up and anchor it in the soil.
  2. Tree roots absorb water and nutrients from the soil. This occurs primarily by thin, non-woody roots.

A history of roots

Did you know that deciduous trees such as oaks, sycamores and many others, evolved after conifer tree such as pines, firs, and cedars? They've developed a more advanced, expansive and efficient root system compared with their evergreen relatives.


One theory suggests that because the leaves of most deciduous trees decompose quickly, these trees may have evolved more extensive and finely divided root systems. That way they can intercept and absorb the nutrients released from the leaves upon decomposition. Just think, all this is going on in your very own front yard.

Learning why trees have specific needs can help us understand our trees better, and take better care of them.