Eugene flowering cherry, dogwood preventive spraying?
I bought a Eugene (College Hill) house where flowering cherry and small dogwood trees have been sprayed for prevention: fall fungicide, winter oil, march fungicide, april fungicide. **Is all/some of this necessary? What is recommended maintenance? I couldn't find relevant OSU Extension online resource. Thanks!
Copper sprays for dogwoods at leaf fall and at leaf bud are to prevent dogwood blight. I do not know if your tree is at risk for that. If not, you can skip this year and see if the symptoms show. If so, resume sprays for next year. One year is not serious for this disease.
Cherries are prone to lots of diseases. Trees under 5 years can be killed, others mostly just look awful with spots and holes in the leaves. Sometimes you will also get bud and twig die-back. If you have had the tree a while under observation and do not see a problem, again you can skip a year, though the dormant spray is cheap insurance, especially if you do it yourself.
The best reference for the sprays is the OSU PNW Disease Management Handbook online. It goes into most of our problems .