Why Are There Yellow Leaves on Trees in Summer?

Why Are There Yellow Leaves on Trees in Summer?

Rich, green leaves are a staple of summer. They’re crisp, bright and a pleasant addition to every landscape. Plus, we love their shady canopy on sunny days.

So if you spot yellowing leaves on your trees, you want them to return to their green glory. An Ontario-based reader recently had a similar goal. She asked us why her river birch leaves were turning yellow and falling off – and how she could fix it.

There are many reasons why you too could see these symptoms. Run down the checklist below to help diagnose your tree.

Test 1: Test for dry soil

If trees aren’t hydrated, the leaves can turn yellow as they try to conserve water.

Test your tree’s moisture by sticking a screwdriver into the soil. If it’s hard to push in, chances are the tree is thirsty and could use a deep watering.

Test 2: Check soil moisture

If the screwdriver test proves there’s moisture deep into the roots, water less.

Your reflex might be to water at the sight of suffering leaves, but overwatering can also lead to yellowing and leaf drop.

Test 3: Inspect and treat

Yellowing leaves and premature leaf drop may point to a leaf disease or summer pest infestation. Consider a free tree inspection to identify the pest or disease and the best treatment.

If an infestation is ruled out, the checkup may reveal a deficiency called chlorosis, which strips leaves of the chlorophyll needed to keep them green.

Begin by performing a soil test and adding any necessary soil amendments. Fertilizer also replenishes lacking nutrients, which in turn helps your tree. Remember, these actions need to happen on a regular basis to have a lasting impact.

Have a question about the appearance of your tree? Comment below for help from our Davey scientists!

  • The Tree Doctor August 29, 2016 >Hi again, Amelia! Ok, got it. Thanks for sharing! You've got a solid plan. Start with those steps, and see if your tree begins to improve. If not, have your arborist inspect your tree for pests when he's fertilizing in the fall. Wishing you and your trees all the best, Amelia. Always here if you need any further help.
  • Amelia Racca August 26, 2016 >Thanks for the info. Yes, my tree faces South. I seldom water the tree and never spray the leaves. The North side of the tree is just now starting to show fall colors. I will check the soil for dryness and will fertilize this fall. Any other advice? Thanks again for the quick response.
  • The Tree Doctor August 26, 2016 >Hi there, Amelia. Oh no - sorry to hear your pruned Japanese maple is struggling. Luckily, you're keeping a close eye on it! Our Davey scientists are curious... What direction is your tree facing? If your tree is facing South, this could be leaf scorch, due to the heat and sun. Also, are you watering your tree during the middle of the day? This could actually magnify the sun on the leaves and brown them. Hope this helps, Amelia. If you'd live to talk more, email us directly at blog@davey.com. Take care.
  • Amelia Racca August 26, 2016 >My Japanese maple's leaves are turning brown at a fast rate starting on one side of the tree. This is new....due to lack of water? Had the tree trimmed by you folks in May 2016. Needs fertilizer? Gropher problem? Thanks for your help.
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