Why Are My Leaves Turning Yellow?

Date October 06, 2020


Author TreeNewal Staff

Lush green tree leaves and tree canopies are a staple of Dallas-Fort Worth summers and early falls. Everywhere you go this time of year, you can see beautiful trees, whether they be the majestic oak trees that grow in our area or another type of tree species. Typically, trees at this time of year still have several bright and dark green leaves that make them look both aesthetically pleasing as well as a great place to sit underneath and enjoy a Texas morning or afternoon.

But, have you noticed that your once green tree leaves are starting to change colors before fall foliage has arrived to our area? Do you have yellow tree leaves on your trees, or yellow tree leaves falling to the ground?

There are a few different tree conditions that could be causing yellow tree leaves. Our ISA Certified Arborists explain what these tree conditions are – and the tree care steps you need to follow to resolve these tree issues – in this blog post. Continue reading to learn more.

Underwatering Your Trees May Cause Yellow Tree Leaves

Sometimes, under-watered trees develop yellow tree leaves. This is because the tree is trying to conserve all the water to which it still has access. In order to check to see if your tree is under-watered, you’ll need to perform the screwdriver test.

Simply grab a Phillips or flathead screwdriver and stick it into the soil underneath your tree. If it’s hard to push the screwdriver into the soil underneath your tree, that means you have dry soil. This dry soil indicates that your tree is under-watered.

To resolve this issue, you’ll need to perform deep watering to get the tree back to a proper moisture state. From then, you’ll need to regularly water the tree to keep it well watered moving forward. After all, proper tree watering is an important tree care task.

To perform deep watering, follow these steps:

  1. Begin by hydrating your trees in the morning.
  2. Set a sprinkler or drop hose up away from the tree trunk and in the “drip zone” of your under-watered tree, which is the area of the tree directly underneath its foliage.
  3. Slowly water the tree, periodically performing the above-mentioned screwdriver test. Once it’s easy to place the screwdriver in the soil directly underneath your tree, you know it’s received enough deep watering.

To properly water your tree after a deep watering treatment, follow these steps:

  1. Water your trees every 2 weeks, preferably in the mornings. You can scale back your tree watering schedule during times of frequent or heavy raining.
  2. Water your trees slowly, using either a sprinkler or a drip hose in the trees’ drip lines.
  3. Apply 10 gallons of water to your tree for every one inch of trunk diameter.

By following these important tree care steps, you can prevent yellow tree leaves from occurring in the future.

Too Much Watering Can Cause Yellow Tree Leaves

While watering trees is an important tree care task, too much water can be a bad thing. One reason for yellow tree leaves is that your tree is actually overwatered.

To determine if your tree is overwatered, you’ll again need to perform the screwdriver test. However, this time, you want to see if the screwdriver goes into the soil underneath the tree too easily. If it does, then you need to scale back on your tree watering scheduled, either in frequency or water amount. Remember, follow the 10 gallons of water for every 1 inch of tree diameter rule to best determine how much water your tree actually needs.

Tree Diseases Such as Oak Tree Diseases Can Cause Yellowing Leaves

Tree diseases, including oak tree diseases that exclusively affect oak trees, can cause yellow tree leaves. Tree diseases often occur when tree pruning is performed out of season. If you perform your own tree pruning, make sure to only do this tree care task between mid to late fall and early spring, during your trees’ dormant seasons. Tree pruning during the dormant season-best prevents trees from developing tree diseases, including fungal tree infections.

If you suspect that out-of-season tree pruning has resulted in a tree disease, our ISA Certified Arborists can help. As part of the professional tree services that we offer to the Dallas-Fort Worth metro area, we inspect trees for tree diseases including oak tree diseases and put together treatment plans to bring trees back to a healthy state. Your tree’s treatment plan may include some tree nutrition with our special fertilizer to properly nourish it so your tree can fight off its tree disease.

Pest Infestations Can Cause Yellow Tree Leaves

In addition to tree diseases, off-season tree pruning can cause pest infestations, which may lead to yellow tree leaves. Sometimes, you can visibility see pests on your tree. Other times, you can look for the following telltale signs of a pest infestation on your tree, including:

  • Yellow tree leaves.
  • Foliage that is suddenly thinning.
  • Borer holes.
  • Abnormally-sized leaves.
  • Stunted branch growth.
  • Holes and frass on your tree’s limbs.
  • Lifting roots.

If you have these signs of a pest infestation on your tree, you need to call our ISA Certified Arborists for help. As part of our professional tree services offerings, we perform environmentally responsible insect control to treat pest infestations and bring your trees back to a healthy state.

We’re Here to Answer All Your Tree Care Questions

Our ISA Certified Arborists we provide professional tree services in the Dallas-Fort Worth metro to several homeowners and commercial properties. We’ve seen lots of yellow tree leaves, and have traced back the exact cause of the leaf discoloration for several clients over the years.

If you’re concerned about yellow tree leaves taking away from the natural beauty of your trees and perhaps even threatening your trees’ health, we’re here for you. We can answer all your questions, help you with tree care suggestions, and provide any professional tree services you may desire. You can reach us today at tel:(817) 592-6846.

To learn more about What Are the Best Times to Prune?, call our Argyle and Southlake based teams

at tel:(817) 592-6846 or send us a message.

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