Please post pictures.

cfreak, ask your neighbor what (s)he did observe to correctly diagnose the problem with the oak? (or whatever the species) tree and share that with us. Or invite her/him to join the forum. Peach Leaf Curl is a fungus disease and the nursery appears to have given factual advice.
You may be able to diagnose the Rhododendron problem from HERE

I cut many of them already but here are photos:

Where do you live?

# 1 & 2 = peach leaf curl. Collect & trash all affected leaves. Mark your calendar to apply dormant spray at the correct time next year.

#3 - citrus -- looks like water spotting (overhead irrigation?) possibly also mites - uncertain about the latter because not really clear

#4 & 5 = Eugenia psyllid - a tiny troublesome insect

#6 (rhody) sunburn &/or water shortage

#9 -- looks like heavenly bamboo -- powdery mildew on a stressed plant.

#10 small succulent - perhaps old mechanical damage w/ leaf spot -- how much water does it get? (It shouldn't get much.)

#11 -- rhody(?) -- OLD sunburn (last year or earlier)

thanks a lot jean001a.

this is very helpful information -- I really appreciate it.