With chlorosis, you should see the leaf veins still green. If all you see is a whitish or bleached leaf, I suspect the plants may be getting too much sun instead. Sunscald should only occur on leaves where the sun hits them directly. Chlorosis will start on a few leaves and spread.

I currently have some signs of chlorosis in a few hydrangeas but plan to take no action. We have had a lot of rain and that can temporarily cause that condition.

Espoma's Garden Sulphur can be used but I noticed better results with Hi-Yield Soil Sulphur. Curious as I switched merely because the other nursery was closed that day. Both are 90% sulphur so I am not sure why the different result.

Espoma suggests using 1/2 cup per established plant or 1/4 cup for newly planted hydrangeas. As usual, water after each application. It may take as long as 4-6 weeks to absorb all the sulphur so re-apply monthly and keep an eye on the Ph Level Number. You want something around 5.5 to 6. If it gets lower than that, quit applying until it reverts back to 6 or above.

Luis

"I was giving them 1 tbs/gallon around the drip line 3x a year"

Mellyz,

My advice would be...if it ain't broke, don't fix it!

I would, in no way consider this to be an "overapplication" of aluminum sulfate and if it is working for you, I would continue. I found the garden sulfer to be less efficient and more costly than the AS. If you have environmental concerns, rest assured that you are not using AS (which is derived from a naturally occurring mineral) in quantities large enough to cause harm......yg

Thank you both for your advice. I think I will use what I have bought in the garden sulfur and see what results I get this summer. Would it be okay to add aluminum sulfate if I dont get the result I want or notice the blooms getting purplish/pink?
Thanks for the help!

I have 8 Endless Summer Hydrangeas that I have babied since last summer. They are full of blooms this year. I was told to add HiYield Aluminum Sulfate to the blue ones. The sack said 2 c to 5 gallons of water. I did this and after reading your comments, I am sick that this might have been the wrong mix.

I regularly apply 1 tbs of AS diluted in 1 gallon weekly. I have 4 4ft bushes full of blooms and still have some pink blooms mixed in with blue and lilac hydrangea flowers. I am scared to add 2 cups of AS to 5 gallons of water or adding 1 cup AS diluted to each 4 ft bush at a time. All so scary. But I will add 2 tbs I stead of one to a gallon of water instead to see if this will aid in bluing some of my pink and lavender colored hydrangeas. Some of mine are even half pink and half blue! I want them all a deep blue. So hard to do.

I have used Holly Tone but not this summer. This summer I have used garden organic sulfur and have used AS. All are fine mixed with good soil, compost and mulch. I have morning sun and pm shade. As I have stated above I weekly add AS to aid in bluing. Will try 2 tbs now to see if it really makes a difference. I wish someone out there could tell me their experience in using 1 cup of AS diluted in water for a 4ft bush and how it effected and if it helped their plant or if someone out there has used 2 cups of AS in 5 gallons of water. Please advise what application really is the best method. Please?

Forget Holly Tone (albeit a good product). I'm using spent coffee grounds (for now). They're free, and I've been drying out ground packets from my Bunn machine at work. They're somewhat high in nitrogen as they decompose, but the high phosphorus content should work in offsetting such.