tj

+oM

Leaf spot(s) are almost always fungal in nature and they too can be exacerbated by moisture. Too late in the season to do anything about them now - nearly all fungicides are prophylactic in nature. Preventative only, not curative.

Just clean up well in fall and destroy or thoroughly compost any fallen leaves. Mulching for winter often helps to smother any spores which may remain or overwinter on the soil surface.

To be on the safe side, you might try spraying with an appropriate fungicide in early spring and/or periodically until the foliage emerges. For now, just keep properly watered through the drought and heat (neither of which dogwoods appreciate in the least). And clean up all fallen leaves in the fall and destroy, so as not to harbor or spread any spores..

I'd recommend listening to the WI comments (more direct experience attributable to Michigan conditions), and acknowledge the quality west coast contributions. Immediate leaping to obscure and worst case suppositions - that may or may not apply to your local condtions - helps no one. Thank you, gardengal48, for being a voice of calm reasoned analysis. Is that even legal to say?

I didn't note that anyone asked after your local conditions (slope, aspect, exposure, soils, hydrology, etc.) and you only mentioned full sun. No one asked - nor did you say - how big this plant was when planted, what condition (bare root, container, B&B) it came to you as, or how big it is now. These kinds of things matter a bit in sorting out what might be a pertinent issue, or what is not.

I have grown Cornus mas here in KY for several decades now, including six large 'Golden Glory' specimens that are about twenty years old. I also have seedling provenanced individuals, and a handful of the clone 'Redstone'. These are excellent landscape plants.

I've also managed large old specimens in estate and institutional landscapes, and observed/admired many many many plants in the eastern United States. I have never seen serious problems of any sort, whether under the highest quality maintenance regimes or basically planted and ignored.

Without benefit of any further information from you (though anything you can provide would always be helpful), I bet you have no major pathogens or problems other than summer drought stress on a young plant, with a little compounded difficulty from air pollution.

A relatively recent transplant tells me that you have a limited established root system with this plant. If it was a small plant, that goes double - less roots take up less water to combat rapid transpiration in long hot weather. If this was a larger plant with a truncated root system, the answer is the same with the added challenge of trying to replace lost roots to support/manage a larger crown of foliage. Despite your watering regime, this was a tough year for new plants to keep up with trying conditions.

As far as the leaf spotting, it certainly could be a fungus - fungal infections can cause leaf spots. I wouldn't let the judgment of one person make the case, however - especially if you plan to launch into a lifelong combat with the pathogen. I'd collect specimens and have them evaluated by trained professionals through your Cooperative Extension Service office, where these situations can be dealt with by plant pathologists at your state land grant university (which your tax dollars have already paid for the service).

I still think your leaf spotting is more likely caused by ground level air pollution (ozone and other emissions), which is well known and quite common in hot summer conditions often found in the eastern United States. Dogwoods can be prone to this problem. You don't need to do anything to resolve this.

Sorry to you (and all) for the long rant, but those who have grown Cornus mas would chuckle at the idea that you would need to do much more than get out of this plant's way and just let it grow. Please reconsider any use of fungicides, as this would be most likely a waste of your money/time, and an additional unnecessary pesticide in your environment. And - since Cornus mas fruit are edible and a wonderful treat in late summer - use of such pesticides would make you less likely to consume them, and possibly a problem for wildlife as well.

I am very interested in hearing more details of your plant, and if you were able to post images - well, that would be gravy.

To wrap: enjoy your Cornelian Cherry Dogwood (or simply Cherry Dogwood, for ease of memory) and its long life. I have enjoyed all of mine for many years, and really appreciate their early subtle spring bloom that announce that the cycle of like approaches anew.

Likewise with insect feeding; Especially in dry summers, insect populations reach a crescendo by late summer. Trees are evolved to deal with this in most cases. Now introduced pests-that's another matter. Many if not most of our serious insect problems have to do with foreign invaders for which native plants, like our Cornus mas, have no resistance to.

But I digress. If I had to lay money down on the future of this plant, I'd be betting on the side that says it will give you years of enjoyment.

+oM

@ wisconsitom: you might double-check, but I'm pretty sure good old Cornus mas is a European/Asian native.

+oM