Proper Watering for Healthy Shade Trees

Shade tree watering diagram

Tree Establishment

When a tree is first planted, even a drought-tolerant and low-water-use species, it needs a period of time to become established in its new environment. Establishing a healthy tree requires careful and proper planting, as well as careful watering and monitoring.

 

Factors to consider when selecting, placing, and caring for trees include: plant species requirements, site conditions, soil type, season, sun exposure, root depth, location of utilities, and emitter placement and flow rate (gallons per hour). Planting in the fall takes advantage of seasonal rains and cooler temperatures, reducing or eliminating the need to apply supplemental water. When planting in the spring, during an unusually dry fall and winter (rainy season), or during hot, windy, and drought conditions, trees may require more frequent, supplemental water.

Tree Watering Guidelines

First check the soil moisture before watering with a probe, screwdriver, or moisture meter about 8 to 12 inches down into the soil. If the soil feels moist and sticky, wait several more days before watering. If soil feels dry and crumbly, then water deeply. Young trees need about 10 to 15 gallons of slow and deep watering per week for the first 3 years of establishment.

 

Both the root ball of a newly installed tree and the surrounding native soil need to receive water to encourage roots to grow out and down into the native soil. The objective is to keep the soil moist, but not water logged or soggy, applying water to the depth of the planting hole so the entire root ball is watered.

Newly Planted Trees and for the First Year After Planting

Water trees planted in the fall or early winter on a weekly basis. Once the rains begin, weekly watering likely won’t be needed. If rain is lacking during this time, continue to water. Newly planted trees need this weekly watering until early spring.

 

When the warm, dry weather begins, water twice a week and throughout the summer months, until the rainy season begins again. During exceptionally hot and windy conditions and in times of drought, trees may need more frequent supplemental water.

Second and Third Years After Planting

Water trees on a weekly basis beginning in late spring and continue through early fall or when the rains begin. During unseasonably dry fall and winter months, hot and windy conditions and in times of drought, trees may need more frequent supplemental water.

Fourth and Fifth Years After Planting

During the summer months, water slowly and deeply two to three times. Most established trees benefit from periodic, yet infrequent and deep watering. Keep in mind, however, that some California native trees, once established, do not want supplemental irrigation during summer months.

Refer to the California Native Plant Society at www.cnps.org for more information about California natives.

General Notes

Watering frequency and duration may need to be adjusted, based upon the plant species, site conditions, soil type, season, sun exposure, root depth, drainage, and the flow rate of emitters (gallon per hour). The objective is for water to be applied slowly so the water will soak into the soil and not result in runoff.

 

Check the irrigation system monthly or at least seasonally, examining soil moisture and site conditions to determine the need and frequency for supplemental water, to adjust the number and placement of drip emitters, and ensure that the system is functioning properly. Check for breaks and leaks, promptly making repairs.

 

For more information about planting and caring for young and mature trees, refer to the International Society of Arboriculture at www.treesaregood.org.

Sources

  • CalPoly San Luis Obispo, Urban Forest Ecosystems Institute, SelecTree: Right Tree, Right Place and Tree Standards & Specifications, Guideline Specifications for Selecting, Planting, and Early Care of Young Trees, https://selectree.calpoly.edu/

  • Hartin, J., Geisel, P., Harivandi, A., and Elkins, R. Sustainable Landscaping in California, How to Conserve Resources and Beautify Your Home Landscape, University of California Division of Agriculture and Natural Resources, ANR Publication 8504, March 2014.

  • Hartin, J., Oki, L., Fujino, D., and Faber, B. Drought Tip, Keeping Plants Alive Under Drought or Water Restrictions, University of California Agriculture and Natural Resources, ANR Publication 8553, October 2015

  • International Society of Arboriculture Trees are Good, www.treesaregood.org.

  • Kemp, B. and Gilman, E. Guideline Specifications for Selecting, Planting, and Early Care of Young Trees, Urban Tree Foundation, California Department of Forestry and Fire Protection, and Western Chapter International Society of Arboriculture, 2011.

  • Regional Water Authority, How to Water Mature Trees, www.BeWaterSmart.org.

  • Reid, K. Landscape Lush – News, views and cues on landscaping in California, Keys to Lush Trees: A Good Drink! Tending Your Trees, Part 2, University of California Agriculture and Natural Resources, May 14, 2018.

  • Sacramento Tree Foundation, Sacramento Municipal Utility District, tips for planting and caring for trees in their first three years of life, www.sactree.com.

  • Schellman, A. and Perry, E. Trees in Your Home Garden, University of California Cooperative Extension, Stanislaus County, A Guide to Choosing & Caring for Landscape Trees, SJ Master Gardeners, 953-6112.

  • University of California Cooperative Extension Master Gardeners, University of California Agriculture and Natural Resources, Information Card: Tree Planting.

  • University of California Agriculture and Natural Resources, California Center for Urban Horticulture, and Ewing Irrigation, Tree Ring Irrigation Contraption (TRIC), https://ccuh.ucdavis.edu/tric.