Don’t Forget to Water Your Mature Trees!

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