I checked two sites for the expression "wake up and smell the roses". I don't think they mean the same -- I mean, one is advising about taking life easy; the other one tells otherwise. (That's how I understood the explanations.)
The usual BrE phrase is wake up and smell the coffee and the meaning is that found in the Merriam-Webster dictionary (=realize what is really happenning). But I found there's also 'stop and smell the roses' with the other meaning (the one from the urban dictionary).
This leads me to believe that the phrase in question is possibly a hybrid derived from the other two expressio