Thank you for your kind response.  I tried to take a picture with my cell phone, but in the bright sunlight was unable to do so.  I will try again with my regular camera and hopefully get clear enough detail of the leaves that have the yellow margin, as well as the little tree.

Oh dear,   my worst fears have been confirmed.  My lovely mimosa trees (I have two of them newly planted in June,}seem to be definately infected with the dreaded wilt.  I went out this morning and the leaves which had yellow on the edges, have turned all yellow, and some have fallen off.  I was under the impression that this wilt  was not a problem in Portland but evidently it is..   There used to be a large number of these trees in my area, but lately I have noticed that there is only one, and some of the branches are bare.

I understand there is no cure for this wilt, but will continue to water them and will feed them with a balanced fertilizer in hopes that they might survive.  If not, I will replace them with flowering cherry trees.  Best wishes.  Alma

Thank you so very much for giving me hope that my wonderful trees may not have the dreaded wilt, and that the yellowing is just something that happens in the fall..   I will continue to water them and feed them a balanced fertilizer.

The good news  and hopefull sign  is that the other branches are all growing beautifully and putting out new growth. My goodness those trees do grow fast.