Your story is great...and how wonderful that you visit your Grandpa so often!
I "rescue" Easter Lillies from our church. People give lillies for Easter services in memory of loved ones, but most don't want them back after a few weeks when they're done blooming. So I take them home and plant them in our cottage perennial border. They come back the following year and bloom beautifully.
We always give a lily in memory of my mom so I think of those beautiful blooming lillies in our garden as a lasting memorial to her.