Thanks again Sue! It's almost bedtime here so I gave a quick look to all the links, tomorrow I'll read them carefully.
I know some plants want an acid soil, but I have a rhododendron (it was hear well before we came in the house) that is beautiful, it grows and blooms in this clay soil, with little water and plenty of sun.
So I guess I'd better stop guessing and see if I can have some test done. Maybe I'm worrying too much, but if I test soil and plants I know for sure.
Thanks a lot!!!!!!!!!