I doubt powdery mildew. I gotta say, it doesn't look so bad to me. It happens on some of my apple trees from time to time, and doesn't seem to be a long term problem. I sometimes think that cold, wet weather brings this on, but I don't really know. :^?

Problem solved. :) Ignore post. This post was edited by Joshiraku on Wed, Jun 4, 14 at 2:51

Thank you Resin! Now I have to decide what to do about the cherry - it is to the left of the lilac and crowding it out. I want it there for the screen but I also want the lilac to thrive. Any advice? We are trying to prevent foot traffic from neighbors through our back yard.

I agree with #1 thru #3 #4 looks like Populus balsamifera (Balsam Poplar) to me. #5 I agree, Tilia americana #6 Most likely Pyrus calleryana - Callery Pear, which is known to many erroneously as "Bradford Pear" because that's the oldest, best selling cultivar. Agree with #7 and #8 #9 Eleagnus umbellata - Autumn Olive #6 and #9 are aggressive exotic invasives which you should consider trying to eradicate, not transplanting. Also, I'd say it's tempting to transplant wild growing trees and shrubs and it can be done with care, but more often than not it ends in failure. Many wild established trees and shrubs, even when still young, resent the root disturbance and don't adjust well and end up dying or taking several years to recover. Some species are exceptions though and it doesn't always end that way, but like I said often times it does. Out of the trees and shrubs you listed, I'd think the smaller Blueberries have the best chance at being transplanted and would behave the best in the landscape.