I'm a rose grower who has battled with growing them for some 16 years. Soil analyses has shown my soil as being adequate in the major elements however lately I've begun to probe the depth of the soil and found it ranges from zero to over 3' the depth of my probe. In my rose beds it averages about 2'. I should have long ago figured that out as shale outcrops on the edge of one of my rose beds. Underlying shale.

Anyway I guess that qualifies as poor. I find that it is amazing how roses vary in their ability to deal with that. Some just shrug it off while others wither and die. No figuring that out just that way it is. So I carefully note commments in rose books that mention, "does well in poor soil". And now plant mostly those and ones from experience have proven themselves. Makes sense doesn't it. I'm a slow learner!

Yet the mention of the term assumes that everyone knows what poor soil is! Beyond soil depth it must also mean in particular structure, nutrients and drainage. Should I also conclude the best way to manage it is to increase the fertilizer and organic matter compared to a deeper soil as there is less to work with for the plant?