Watering Trees - Ask Extension
Hello there, I live here in Bend, but I've only been here a few years growing up on the East coast. I'm trying to determine if and when/how much I sho...
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Watering Trees #874002
Asked June 20, 2024, 7:30 PM EDT
Hello there, I live here in Bend, but I've only been here a few years growing up on the East coast. I'm trying to determine if and when/how much I should water trees on my property. Specifically I have established ponderosa trees, probably 10 years +, a juniper, and an older deciduous tree, I'm not sure which type.
I've read conflicting things, that make me think I should water during the summer, and for example this from ODF:
"Some native trees, such as Oregon white oak, most California oaks, and ponderosa pine should not be watered after their first couple of years."
My instinct is that I should be water the trees, as my home is being built, I was going to use Tree bags to water, But maybe a deep watering at night is better? I'd appreciate any guidance on watering trees. Thank you!
Deschutes County Oregon
Expert Response
Hi Shane:
Yes, you should water your trees, especially with the drought cycle we are in. Trees need water at their driplines – where tree roots extend to the outermost branch tips and in the top 12-18 inches of soil. Tree bags will not accomplish this, they will only get water to the root ball and not go deep enough to really help the tree. The simplest method is a hose end sprinkler with spray going out to the outermost branch tips. Soil water absorption in Central Oregon is about 2 inches per hour. That's a sandy soil profile. You may need more or less time depending on your individual situation. You can probe the soil at the outer branch line to see how deep the water is going. How frequently depends on the type of soil also. With a well established tree, I would water every 3-4 weeks. Younger trees will need more frequent attention. I'm going to attach a couple of documents that dive into more detail, if you are interested.
Water-wise Gardening in Central Oregon gives lots of information for your yard and garden planning. The end of the bulletin also lists links to many other helpful sources for Central Oregon landscapes.
Efficient Irrigation of Trees and Shrubs was written 20 years ago but the same principles apply.
Thank you for your question,
Yes, you should water your trees, especially with the drought cycle we are in. Trees need water at their driplines – where tree roots extend to the outermost branch tips and in the top 12-18 inches of soil. Tree bags will not accomplish this, they will only get water to the root ball and not go deep enough to really help the tree. The simplest method is a hose end sprinkler with spray going out to the outermost branch tips. Soil water absorption in Central Oregon is about 2 inches per hour. That's a sandy soil profile. You may need more or less time depending on your individual situation. You can probe the soil at the outer branch line to see how deep the water is going. How frequently depends on the type of soil also. With a well established tree, I would water every 3-4 weeks. Younger trees will need more frequent attention. I'm going to attach a couple of documents that dive into more detail, if you are interested.
Water-wise Gardening in Central Oregon gives lots of information for your yard and garden planning. The end of the bulletin also lists links to many other helpful sources for Central Oregon landscapes.
Efficient Irrigation of Trees and Shrubs was written 20 years ago but the same principles apply.
Thank you for your question,
Thanks very much Cristi, this is very helpful!
You're welcome...
