My Red Twig Dogwoods look so icky!
Good Afternoon! I am stymied and the few folks I have discussed this with do not seem to know the issue either. I have had a number of Red Twig Dogwoods around my yard for a few years now - each year this spotted, sparse issue seems to happen to the same ones, some are doing just fine. They are in a morning to early afternoon sunny spot. (I can not seem to get the pic to send) I am wondering if it is a bad location issue (but some nearby are doing fine) or a plant itself issue. Any advise, suggestions would be much appreciated!
It sounds like your dogwood has a leaf spot disease, probably fungal. Septoria is a common problem. Here is information about the disease and control methods: http://extension.missouri.edu/adair/septoria.aspx A photo would be helpful for a specific diagnosis.
If you are seeing different levels of the disease among your shrub dogwoods, that can be because their sites are slightly different, even though in the same bed (more shade or different soil, different slope). Also, different varieties of the same plant can have different susceptibility to a disease. Even individual plants have some different levels of hardiness just like humans.
What would be a recommended course of action if this is an annual disease issue? The shrubs are about 6', very sparse foliage
Please read the controls suggested in the first link above.
Septoria is a common problem, unfortunately. You'll have to decide how must effort you want to put into improving the appearance of your dogwoods. You can try just sanitation first (removing fallen infected leaves--a leaf blower is good).
In addition to removing leaves, prune it back below the dark stem cankers. This removes even more of the infectious material. Since new stems are the reddest, this stimulates nice new clean red growth anyway.
If that doesn't work, you might try the fungicides mentioned in the link.
If neither suits you, you'll have to decide how much spotting you are willing to tolerate.
Thanks for your help, much appreciated!