How much to water my yard trees - Ask Extension
I have a 20x40 lawn area surrounded by 6 box elder trees, 3 Port Orford cedars, and one incense cedar. I have always watered the lawn every 4 to 7 day...
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How much to water my yard trees #926926
Asked March 27, 2026, 5:43 PM EDT
I have a 20x40 lawn area surrounded by 6 box elder trees, 3 Port Orford cedars, and one incense cedar. I have always watered the lawn every 4 to 7 days in the summer so that the trees have enough water, but I am concerned that we might not have much water this summer and wonder what is the minimum I can water them and still keep them healthy. I live in Ashland, on the north-facing hillside, above Siskiyou Blvd.
I also have a 5-year-old-mimosa tree on the other side of the house that has received monthly water in the past. Will it be ok without any additional water this year or should I keep up the monthly soaking?
Jackson County Oregon
Expert Response
As trees increase in size, they become increasingly valuable. Mature trees usually receive supplemental water when you water shrubs or lawn areas. If you water your shrubs less and let your lawn go dormant during times of water restrictions, you might want to water your trees deeply every 2 weeks or so. Prematurely shedding leaves are a sign of drought stress. If your trees begin dropping leaves, increase your watering frequency.
Water trees in our area by focusing on slow, deep, and infrequent watering to establish strong roots, generally from May through September. Apply 10–15 gallons per week for young trees (3 years or younger) and 20–25 gallons weekly for 4–10-year-old trees, using soaker hoses or drip lines.
Key Watering Strategies: use soaker hoses to avoid surface evaporation and run-off; Deep soakings once or twice a month are better for mature trees, while young trees need weekly attention; Water in the early morning or late evening to minimize evaporation; Apply water at the tree's drip line (outer edge of the canopy) rather than directly against the trunk; Apply a 2-3 inch layer of mulch around the tree to retain moisture, but keep it away from the bark.
During heatwaves, increase watering frequency, especially for young trees, as they may need water twice a week in 90°F+ temperatures. If you have clay soil, apply water slowly to avoid pooling.
Here is a publication for more information: https://extension.oregonstate.edu/catalog/em-9125-conserving-water-your-yard-garden
Water trees in our area by focusing on slow, deep, and infrequent watering to establish strong roots, generally from May through September. Apply 10–15 gallons per week for young trees (3 years or younger) and 20–25 gallons weekly for 4–10-year-old trees, using soaker hoses or drip lines.
Key Watering Strategies: use soaker hoses to avoid surface evaporation and run-off; Deep soakings once or twice a month are better for mature trees, while young trees need weekly attention; Water in the early morning or late evening to minimize evaporation; Apply water at the tree's drip line (outer edge of the canopy) rather than directly against the trunk; Apply a 2-3 inch layer of mulch around the tree to retain moisture, but keep it away from the bark.
During heatwaves, increase watering frequency, especially for young trees, as they may need water twice a week in 90°F+ temperatures. If you have clay soil, apply water slowly to avoid pooling.
Here is a publication for more information: https://extension.oregonstate.edu/catalog/em-9125-conserving-water-your-yard-garden
