Pink Dogwood tree
We have a pink dogwood tree in our front yard that recently hasn't been looking so good. The leaves look a bit wilty and curled, and have a mottled appearance. It is exposed to full sun most of the day, but hasn't had issues for the past year we have lived here. Any idea as to what is causing this, and measures we can take?
Washington County Oregon
Appropriate growing conditions help all plants resist and wide range of biological diseases and abiotic problems.
Thanks for the good clear photos of affected leaves --but for a complete diagnosis we really need additional info. It would be great to see photos of unaffected leaves, and to know if a) all the leaves are affected, or b) leaves at the ends of branches are more affected, or c) leaves closest to the base of branches are most affected. Photos are great --frequently better than specimens (because the specimens people bring in are either the parts they can reach, or the most affected parts. Close up photos, like these, need to be augmented with good photos of the whole plant (to show distribution of the problem) AND photos of the plant in the landscape --we learn a lot by looking at the condition of surrounding plants, structures, and ground conditions.
The verbal narrative that clients send with the photos is also always helpful. Even when plants clearly are being affected by a pest or disease, that attack is most often due to a non-biological change, condition, or deficiency. Things like too much or too little water, increased or decreased shade, nearby construction, unusual weather conditions, etc. etc. --changes in environment and in care can favor pests and diseases, or favor plant health. The right plant, in the right place, getting the right care is surprisingly resistant to most biological pests.
That said, this analysis is in part an exercise in reading tea leaves, and you might want to contact your local Master Gardener phone (email) clinic with additional photos and expanded narrative. Contact info for the three offices in the tri-county area is here: https://extension.oregonstate.edu/mg/metro/have-gardening-question
But based on what we have here: a) The small but severe browning on the tips of a few of the leaves indicates that those leaves recently were not getting adequate water. Given how that browning is really small and only at the very tips, your watering has probably been pretty good so far this year. But watch going on into the summer. Dogwoods like a lot of summer water--they are NOT drought tolerant, by any definition. B) You mention that this dogwood is in full sun--in the wild, dogwoods are understory forest plants, always partly shaded by larger trees. They like growing in forest duff, so if yours is growing in bare ground, put down two or three inches of mulch (barkdust or tree chips) all the way out beyond the drip line. And if is growing in a lawn or among weeds, remove those from the area out to the drip line also. C) You mention that the dogwood "hasn't had issues for the past year we have lived here". If you are new to the house, you might well find that the leaf mottling actually has been happening many or even most years for several years.... If you have an observant next door neighbor, ask them if they have noticed.
About the mottling itself: nurses have a saying, "If you hear hoofbeats, look for horses, not zebras." The most common cause of lots of slightly discolored leaves without dead spots is a mineral deficiency, and in this case, this could be a minor nitrogen deficiency. This is very common, as nitrogen, unlike almost all other plant nutrients, washes quickly out of our soils. Try distributing a little high-nitrogen fertilizer around the entire area covered by branches. Water it in well, and see if the mottling goes away. Nitrogen deficiency is the "horses" solution.
And the "zebras" option? Dogwoods actually are somewhat susceptible to any of several mosaic viruses. The mottling in your photos actually looks more like virus than nitrogen deficiency, but because the nitrogen deficiency is so much more common, try adding fertilizer first. There is no treatment for virus. Once the plant gets a virus it is quickly distributed throughout the plant. On the other hand, if this IS a virus, providing excellent care --summer water, mulch, adequate shade may allow your dogwood to survive and bloom for many years.