Don’t Forget to Water Your Mature Trees!

Jesse JenkinsBest Practices, Timely Tips, Trees10 Comments

The rains this week are excellent (!!!), but not enough to water your established, mature trees sufficiently. We spend a lot of time making sure our plants and lawns get plenty of water, but don’t forget about your big trees! Here’s what we recommend.

Trees, especially mature shade trees, provide huge benefits for our environment and they’re difficult and expensive to replace. How could you even put a price tag on a 30-year-old mature Oak tree? 

With summer temps and a lack of depth moisture in the ground, mature trees need a slow, deep watering every 2 to 4 weeks. If your trees are showing signs of stress, (looking dull, dropping leaves), water them deeply once a week to rehydrate. You can accomplish proper, deep watering by placing a sprinkler between the trunk of the tree and the drip line (edge of the tree canopy) and running it for 45 mins. Then, move the sprinkler 1/3 of the way around the tree and repeat until you’ve watered all the way around. Check your sprinkler placement to be sure you’re not watering the street, the sidewalk, etc. Here’s a simple top-view illustration. 

Speaking of stressed trees, I encountered a strange one this week. I noticed that the trunk of my old Ash tree in the front yard appeared to be “sweating”. Upon closer inspection, it was oozing a foamy, white substance that smells like rotting fruit or sour beer – not pleasant to me, but the flies and bees were loving it!

I called John Wood at Tree Amigos who confirmed that this is a bacterial infection known as Slime Flux or Bacterial Wetwood that typically presents when trees are stressed in the summer. Unfortunately this is a serious issue and a sign that the tree is nearing the end of it’s life cycle. John gave me a great piece of tree advice: don’t remove the tree yet unless it poses a risk to people or property. Once the tree starts to “take itself apart”, i.e. once a large branch falls unprovoked by high winds, then it’s time to cut it down.

– Jesse

10 Comments on “Don’t Forget to Water Your Mature Trees!”

  1. Thanks Jesse. Luckily we have an irrigation system that waters once a week. Our large Live and Red Oaks seem to be doing fine, so hopefully we are doing enough.

    1. Right on, Tom. Just make sure your irrigation is watering at the drip line of the mature trees. You may want to supplement with a more targeted tree watering from time to time.

  2. Bummer Jesse! I have a 15 year old Cedar Elm that has a vertical crack down the center of the trunk. John has been helping me as well by removing some limbs to lessen the weight to nurse this tree along. I hate to lose the shade it provides. What is a fast growing, drought and freeze tolerant tree? I need to plan a replacement soon!!

    1. Hey Neighbor! Yes, such a bummer to eventually lose a big tree. We love our Cedar Elms here at Gill’s. If/when they need replacing, I bet we’ll go back with another one. You might also think about a Natchez Crape Myrtle. Good drought tolerance and fast growth once established.

  3. I live in Rockport on Live Oak Peninsula and have mostly sand. Do I follow this same watering technique for my oak trees? I have some very big and old trees that are important for shade and beautiful to behold. Thanks

  4. Thanks for the advice! I have an oak that was planted too close to the house. The ground around it has the driveway, the garage, the house, a patio, and a bricked in walk way. There is a little bit of available ground for watering. I can obviously water in those places but concerned for the tree (and the house for that matter). Suggestions?

    1. Hi Diane – good question. I would recommend talking to Tree Amigos about the tree if you’re concerned that it may affect your house/foundation.

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