Pale Hydrangea Leaves

Question: Good afternoon, 

Why are the leaves on my hydrangea so pale?  See attached photos.  Also, both shrubs have never flowered until this year. 
These hydrangeas  have been in place for five years. 

Thanks,
Chuck Donahue

responder: An Ask Extension Expert Replied July 25, 2024, 8:32 PM EDT
response: Thanks for your question. Look carefully at the leaves of your hydrangea. Can you see where the veins in the leaf are quite green whereas the rest of the leaf, as you noted, is a yellowish-pale. The fancy name for this is condition is chlorosis This is usually a sign that the plant has a magnesium and/or an iron deficiency. See: https://www.nurserymag.com/article/hydrangea-primer-nutrient-management/ - :~:text=Magnesium (Mg) deficiency first occurs,or shallow but appear healthy. https://www.weekand.com/home-garden/article/magnesium-hydrangeas-18029022.php At this next site, scroll down to where magnesium and iron deficiencies are discussed: https://www.rhs.org.uk/prevention-protection/nutrient-deficiencies The knee jerk response might be to just add magnesium and/or iron to the soil. Unfortunately, it’s not quite that simple. Generally, hydrangea need to be grown in soil where the pH is close to 6. This is a rather acidic soil. If the pH is higher than this, more towards the alkaline region, hydrangeas simply are unable to take up these nutrients even though they may be abundantly present in the soil. Your first step should be to determine the pH of the soil. There are DIY kits that you can purchase at gardening centers whereby you can determine soil pH yourself. Regrettably, these are often unreliable. I would strongly suggest that you consider submitting one or more soil samples for analysis by the University of Minnesota Soil Testing Laboratory. There will be a nominal fee for this. See:  https://soiltest.cfans.umn.edu/testing-services/lawn-garden If you decide to go this route, first give the laboratory a call and see if besides measuring soil pH, they could also determine soil magnesium and iron concentrations. Unfortunately without this information, you will not have a factual basis upon which to take remedial action. Good Luck. I’m going to leave your question open for a while so that if you do have a soil analysis done and have a picture of the report sent to me, that picture will be appended to this current question thread.  I hope that we’ll be able to continue our communication so that your hydrangeas can be restored to their previous state. Thanks for consulting our forum.

responder: An Ask Extension Expert Replied July 30, 2024, 7:02 PM EDT
response: Just checking on what progress you might have made with respect to your hydrangea. any update would be appreciated. Thanks on behalf of our forum.

responder: An Ask Extension Expert Replied August 01, 2024, 8:44 AM EDT
response: Good morning.  In order for me to keep your question open so that I could receive comments from you, I would like to know what your thoughts are regarding having a soil analysis done.   Many thanks.  We would like to continue working with you.

responder: The Question Asker Replied August 06, 2024, 1:40 PM EDT
response: ﻿Good morning!  I am fully intending to send/ bring you folks a soil sample.   Just waiting for my schedule and Mother Nature’s to coincide. Looks like today’s the day!   I want to make sure that iron and magnesium are tested.  Thanks for your support!  Chuck Donahue   Sent from my iPhone On Aug 1, 2024, at 7:45 AM, Ask Extension <<personal data hidden>> wrote:   ﻿

responder: An Ask Extension Expert Replied August 13, 2024, 5:26 PM EDT
response: Just checking on the status of your soil report? Thanks for making use of our forum.

responder: An Ask Extension Expert Replied August 16, 2024, 5:08 PM EDT
response: In the absence of hearing further from you, I will be closing your question tomorrow (8/17) night.  Hopefully we will be able to move on with your situation.

responder: An Ask Extension Expert Replied August 17, 2024, 12:09 PM EDT
response: In the absence of hearing further from you, I will be closing your question tomorrow (8/17) night.  Hopefully we will be able to move on with your situation.