In the episode where Blanche's husband's son shows up, Rose told Blanche not to throw away her memories of George just because of something that he did...

In the episode where George shows up (the dream episode) where Blanche is ready to go out on a date while George keeps calling, Rose said "Tell him you love him, tell him you hate him...do it for all of us who wish we had the chance"...

In the episode where Blanche goes out with Dorothy's blind date (Ken Howard), at the end Rose says "Take it slow, an old-fashioned romance...how does that make you feel?" to which Blanche replies "Like a Lady" (BTW...this episode always brings a tear to my eyes because you really see Blanche's vulnerability and innocence).

So...while she is considered the "ditz" of the group, beyond the ditziness is always a bit of wisdom...