I think the poem idea is wonderful.

My mom was a teacher and, to be honest, while teachers appreciate all the knickknacks that their students give them, getting the same stuff all the time can become a bit of a nuisance. My mom always felt bad getting rid of things, and there was always enough of a surfeit of stuff that we could never use it all, especially things like mugs and candles and fancy notepaper. When I got a chance to try to go through stuff from my house last summer, there were boxes and boxes just full of unused stuff.

Your note, poem, and song quote sound like a great, heartfelt gift that I'm sure she'll appreciate.