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This is my first hydrangea, it is an "Endless Summer". Are the black spots a disease, fungus? Poor thing was ignored all summer, it started to fry and we covered it with a shade cloth. I was happy to see it still blooming since I thought all hydrangea's only bloomed early in the season. I since looked up this one in PF (again) for a refresher course!
It may be some type of fungus, I would probably leave it alone since it doesn't seem to be threatening the life of the plant and its leaves will drop before too long anyway. So as long as it doesn't get any worse, I would leave it be and when the leaves do fall make sure to pick them all up to reduce the chance of the fungus sticking around and coming back next year. Some fungi are spread by splashing water from overhead irrigation, so I would be careful not to splash the leaves when you're watering it and that should help too. If someone else comes along and tells you something different though please trust them--I've never seen this before and out here it's so dry in the summer that I have never had any sort of fungus problems with hydrangeas.
I think you should heed Ecrane3's advice. It looks like a leaf spot fungus, caused by overhead watering combined with hot/humid conditions. It shouldn't hurt the plant. Next year, spray with Messenger or the fungicide of your choice as the plant starts leafing out, and stick to watering at the base of the plant and you should be fine. Messenger works better than fungicide, I find. It helps the plant resist the fungus in the first place.
Hmmm...I just came to this forum to post the same inquiry! I've been stymied by it, too!
Many of my hydrangeas show that spot and then it usually worsens. Some of them do get overhead watering so perhaps that's the culprit, eh? (It's almost hard NOT to get water on the leaves because all my hydrangeas are in small pots being grown out for future sales in gallon pots one day.)
Kim, mine usually evolve into this: (see pic). I've just been pulling the dead leaves of and the plant seems to do just fine (so far!)
And, by the way...while I'm here. Does this symptom below appear to be something common with hydrangeas?
I am seeing quite a bit of yellowing mottling on some of the leaves and it is most often on the younger leaves. Often times yellowing of leaves has to do with a nitrogen deficiency if it is on the older leaves so I don't feel it is that. I'm using Osmocote for these plants so perhaps there is some other nutritional deficiency?
That looks like chlorosis, which is actually iron deficiency not nitrogen. So I would apply something with iron, also check the pH of your soil because if the soil's too alkaline then the plant can't absorb the iron.
Kim, I had the same question at the end of last summer. It was my first hydrangea. Turns out it was too much sun. This year I had 3. I moved 1 to a spot with total afternoon shade and 2 others still got a bit more frying in the sun than it would have liked. The one in total afternoon shade had no spots, the others did have a few.
I think mine spots are from the sun coupled with water on the leaves from rain. Maybe I picked the wrong spot for it with so much sun. I was hoping that when it was established it could tolerate lots of sun better.
Ladyborg and bluekat...I've got some in more shadier areas that don't seem to have the black spots as much or at all as others. Of course now, the ones in the shadier areas also don't get direct overhead watering so you may be on to something (bluekat).
The one's I'm growing are an old Japanese cultivar called "Blue Bird".
Me too. This is a first for me. I planted 5 new Hydrangea this yr & only Mathilda Gutges got this ugly fungus. Also, I have what looks like the same fungus on all my peonies. They are nowhere near the Hydrangea. Peonies &all other Hydrangea are 15 yrs.old. The fungus appeared after blooming was over.
I have drip hoses everywhere, but I have always supplemented with sprinklers. Never had this before. After destroying the dropped foliage, can I spray w/ Messenger on the gound this year? KThis fungus is particularly ugly, Grrr
Messenger won't do anything if you spray it on the ground, it's only good as a foliar spray. Also it doesn't actually kill bugs/fungus, it gives the plant's immune system a boost to help it fight off the intruder. There's really not much you can do to get rid of soil-borne fungi, the way you minimize the chance of it affecting your plant next year are get rid of this year's diseased leaves, and then be careful not to splash the leaves while watering (drip irrigation is much better in these situations than overhead watering)