Hydrangea leaves have brown spots on them

12 years ago

My hudrangea has flowered beautifully this summer and I've done nothing to it. I just noticed today that the several of the leaves have brown spots on them. Any ideas what this could be from and what I can do about it.

Comments (4)

moshie01
Original Author
12 years ago
Here's a picture of the brown spots on the hyndrangea leaves

Here is a link that might be useful:
luis_pr
12 years ago
It looks like a fungal infection called leaf spots, caused by too much humidity and-or overhead watering. I would try to control it by making the environment less humid and using good cleaning practices.

There is no way to control humidity from storms but you can control waterings by making the sprinkler water early in the mornings. If you do overhead watering by hand, you can water the soil instead early in the mornings. If your mulch is often moist or wet, you are watering too much. You can switch to water when a finger inserted to a depth of 4" feels almost dry or dry. Separate shrubs from each other to improve air flow, which will reduce humidity levels.

You can also throw in the trash plant debris found under the bush, replace the mulch with new mulch when more than a third of the leaves are affected, dispose in the trash all the dried out blooms and dried out leaves in the Fall.

You can also try to use fungicides but they can be expensive and we are so close to the end of the growing season (when the leaves dry out anyway) that it is a toss as whether one should apply it or not. I guess if you have a considerable number of leaves infected, you should replace the mulch (it is probably full of spores) and spray sulfur-based fungicides on the leaves (top and bottom) as well as in the stems. If you have an organic regimen in your garden, consider applying a copper fungicide. Affected leaves will not be cured back to all green by fungicides. A drip irrigation system can help reduce this problem too.

Note: in order to minimize spread of the fungal infection, it is best to throw away in the trash the dried out leaves, not in the compost pile (if you have one). Do the same with the spent blooms when you deadhead (throw them in the trach).

Luis
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Sorry, in my own little writing world right now. Apparently I didn't come out fully when I wrote that upthread... Never fert a stressed plant, and I don't know that anything will really fix the fact that some leaf tissues died and the decomposers are moving in, as we expect. I had a Philadelphus get hit a couple weeks ago with a little fungus (very odd here where we expect single-digit humidity). I squirted with neem and removed a couple branch tips and it took care of itself. If yours spreads to more leaves, remove affected lvs, coat the plant with neem around dawn or dusk, otherwise it should just run its course, hit a few lvs and go away - provided the diagnosis is correct...probably lots of that in your part of the country this year. HTH. Dan
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It looks like bacteria spot. If it is bacteria spot, the spots will turn to holes. Not much you can do but get disease resistant varieties. Some of mine get it every year but usually it is in the late summer. I doubt the spray had anything to do with it. The tree looks healthy. When you sprayed for ants you probably also had aphids. The ants like to protect the aphids so they can eat the honey dew that the aphids secrete. With stone fruit the biggest problems are brown rot, worms (oriental tip moth and plum curculio) and scale. The brown rot can be controlled with fungicides. Tip moth and plum curculio can be controlled by insecticides sprayed when you see the fruits bitten by the beetles. Scale can be controlled by a dormant oil spray in the winter, and some add copper to the last dormant oil spray to help control brown rot and bacteria canker. It is easier to have 4 separate trees than a multigraft, but since it was a gift not much you could have done about that. You will have to prune to keep all the four branches about the same size so one does not dominate the others.
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poetry1959
9 years ago
Thanks for the information! My hydrangea leaves & stems have them, too. I live in FL, where it's already humid, but this year we had a "two hundred year flood". I'm hoping by next year, they will have had a chance to recover.
luis_pr
9 years ago
Oh, wow! I was unaware that it was raining a lot in parts of FL. It has not made the news yet. Out of curiosity, in what part of FL are you?

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Hydrangea leaves have brown spots on them

Comments (4)

moshie01
Original Author

luis_pr

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Hydrangea leaves have brown spots on them

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moshie01Original Author

luis_pr

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luis_pr

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moshie01
Original Author