I don't like being the one to burst bubbles, but I'm betting that the nice pretty red spots you see are signs of a fungus infection. I see leaf spot type fungus on my leaves and it's very clear on the leaves that it a leaf spot. I've also been noticing that some flowers will have this spotting on the flowers that you're talking about, especially late in the season. And here lately, I've begun to see that the plants with the most spotting on the leaves are the same ones with the pretty spots on the flowers. I think the problem is more apparent on the flowers than on the leaves, so that you can see the flowers spotting, but not so much on the leaves, and you might then not so readily see the connection.

I have in the back of my mind a working hypothesis that the browning of the flowers in the summer that we attribute to the sun burning could be in actuality a fungus,too. I have essentially nothing to support this thought other than my intuition.

I don't have any thing other than my observations to support what I'm saying here. My humble opinion. Hay.

Speckling on flowers can also be the effect of water damage - rainfall or overhead watering followed by sun as the flowers emerge can have a similar result. I'm not familiar with any hydrangea flowers that normally feature this spotting.

Thanks for the input! A little disappointing as they really were rather striking. Wish I'd taken a picture!

Cheers,

Jackie

It's still very pretty, don't you think?

My humble opinion again, but I don't think that overhead watering and sun would produce anything like this effect.

Hay.

It is hard to say what it is that you saw without pictures.

It might not be a disease at all. One of hydrangeas, called 'Preziosa' exhibit red pinky spottings on the flowers as they aged. It is pretty and my shrub is healthy so I don't think it is a form of disease.

I hope that you won't mind if I disagree with you.

I'm healthy, too, but I'm sure there are lots of fungus, bacteria and who knows what else living all over my body. Hydrangeas are well known to be susceptible to fungus and powdery mildew. Powdery mildew is quite easily seen and you'll see it forming in late summer and, for me, by this time of year, I see all sorts of signs of powdery mildew on much of my hydrangeas. I imagine it's the peak of the season for fungus.

I think I can see signs of powdery mildew in lerissa's pictures. It's the white dusty look on the leaves, especially visible in the bottom picture in the middle of the right edge. And I think that the blackness that you can see in some of the first pictures leaves could be a fungus, too.

Fungus comes on strong in the late summer and that's just when the flowers start to show these spots. Look closely at some of these spots. Don't they just look like leaf spot to you? If I look really closely, I can see some of the interior of these spots actually turning brown.

For me it looks like the more powdery mildew on the plant, the more speckled is the flower. It's across varieties, too.

{{gwi:1021844}} The plant on top is a Nikko or All Summer Beauty that's got it's share of powdery mildew. The plant on the bottom is Endless Summer that shows very litte signs of any fungus of any kind. There is still some spots on the Endless Summer flowers, but hardly noticable. Within Nikkos that I have, this difference shows up, but Endless Summer was so much more disease and spot free.

I have some Preziosa and they got the most spots very early and they were also the ones that got the most powdery mildew very early. At this point, the plants are completely covered with mildew and the flowers are pretty much brown.

Hay.

I just googled "flower, spot, fungus" and found a couple of pictures you might find interesting.

Here's a rose. Doesn't that have that familiar look?

And here is a rhododendrum leaf with leaf spot.Doesn't that look familiar?

Hay.

Hay,

I know what powdery mildew looks like. And these picture were taken sometime in the fall last year. Certainly, the shrub might not be in its peak glory.

I don't like the look of those pink freckles on the roses but they do look nice on the Preziosa blooms. I've been super busy lately but I'll keep an eye on my Preziosa shrub if it is indeed caused by disease.

Very interesting...I thought those speckles on Preziosa were just a character trait (you see them all the time in photos) but in looking closely at these photos, I can see exactly what Hay is talking about. I must say however, it is one of the prettiest funguses(?) I have ever seen and looking at the first picture, I can totally understand why Pickles33 wouldn't suspect anything was amiss. Thanks AGAIN Hay for the lesson and the keen eye......yg

Thanks so much for all of your input! I've never experienced powerdery mildew on any of my hydrangeas (although I have lots on my dahlias & mondarda!). Lerissa's pictures of the preziosa blooms look exactly like what I saw in North Yorkshire. No surprise that the hydrangeas there would suffer from mildew as it tends to be a little damp up there.

Cheers, Jackie

My Preziosa won the award this summer for the Most Diseased.

You know the brown that we get on the top of blooms in the late summer on many of the ones we have in the sun? I always thought that was somehow just the sun and water doing something to kill off the delicate petal tissue and it then just naturally turned brown somehow. But maybe all that is the work of fungus. Fungus that loves these top petals for some reason.

That same brown-ness I see on the flowers of many of my plants that are the most infected with obvious fungus at this time of year. On the healthiest plants, the flowers are still wonderful colors. Here's {{gwi:1021845}}

Botrytis Cinarea is one fungus that is on the list of Hydrangea fungus. Apparently very common and the cause of a lot of rot in this world. Not all of it bad, though. Pour yourself a nice glass of Sauterne, sit back, and read this

Hay.

My Preziosa has the same problem now. Just wanted to find out if it will persist the next year too. Is there any remedy?

Thanks
Tina

Since this old thread had been resurrected I think I should chime in and say that I respectfully disagree with Hay's opinion.
While I totaly agree with him that overhead watering + funguses could cause red spots on a leaves the same couldn't cause red speckles/spots on a petals.
IMO, it's a genetic issue related to the parentage of the plant and ability of the red pigment in some cultivars to become transparent at some point of the yearly life cycle of the flowers. Namely in mid August-September, when flowers start aging.
Here are some illustration to the thesis.
This is the 'Sister Teresa' as healthy as it gets (I'm not about to inspect every single leaf to find some imperfections) and all her pristine white July's blooms always become red speckled in August

Here is Preziosa

Hobelle in September is nothing but red speckles and dots on green flowers

but it is just in transition to her October glory-time