In Tennessee Williams's play The Glass Menagerie, the character of Laura Wingfield is characterized as a young woman whose foot malformation makes her limp. This is considered a flaw to her physique, which makes her even more shy than she naturally is.
Laura Wingfield fits the description of a person who suffers deeply from social anxiety, and her option becomes to remain a recluse to her own home, under the care and over-protection of her mother, and holding on to the memories of her high school years, to this day.
One of the memories that binds Laura to her past is that of Jim O'Conner, a once-popular high school classmate of Laura's whose charm and looks made him Laura's first love interest. This is when the term "blue roses" comes in. For, it is during one of Laura's absences caused by illness that she is able to establish contact with Jim.
LAURA: When I had that attack of pleurosis - he asked me what was the matter when I came back. I Said pleurosis he thought that I said Blue Roses ! So that's what he always called me after that. Whenever he saw me, he'd holler, 'Hello, Blue Roses ! I didn't care for the girl that he went out with. [..] It says in the Personal Section - they're engaged. That's - six years ago ! They must be married by now.
Here we have a classic example of the person who is so stuck to a small cyclical life that, six years later, she still holds the past as if it had just happened the day before. The "blue roses" instill in the audience the image of something extremely rare and sensitive. This is the same image that Laura instills in the reader: a woman like her is unique, not only in her physical limitations, but also in the fact that she is so fragile and soft that she is almost easily breakable.
When you analyze the symbolism of the blue roses, it is interesting to see that it is an imaginary object, one that brings Laura in contact with reality.
JIM [smiling doubtfully]: You know I have an idea I've seen you before. I had that idea soon as you opened the door. It seemed almost like I was about to remember your name. But the name that I started to call you - wasn't a' name! And so I stopped myself before I said it.
LAURA: Wasn't it - Blue Roses?
JIM: [springs up. Grinning]: Blue Roses ! - My gosh, yes - Blue Roses! That's what I had on my tongue when you opened the door ![..]I didn't even know you were Shakespeare's sister! Gosh, I'm sorry.
In other words, Jim is real. High School was real. Laura's needs are real. However, the allegorical mention of "blue roses", ironically, bridges Laura's world from fantasy to reality.
We know, however, that it will not remain so. Jim is, indeed engaged to be married, and the economy has reduced him from high school hero to a regular factory worker with hopes to make a better life. The Jim that Laura remembers is the same one that she has kept in her imagination for years.
To Jim, however, Laura's uniqueness is just like that of the blue roses. As sensible, soft, and special as the blue rose would be.
I wish that you were my sister. I'd teach you to have some confidence in yourself. The different people are not like other people, but being different is nothing to be ashamed of. Because other people are not such wonderful people. They're one hundred times one thousand. You're one times one! They walk all over the earth. You just stay here. They're common as - weeds, -but - you - well, you're - Blue Roses!