Susan, I have no idea if it's as tall as it gets. It came with the house we bought, and we only moved in about a month ago. The one I had in Utah was very small compared to this one. We've nicknamed it RPG, for Rocket Propelled Grenade. That is what the flowers look like to us. It's planted right next to the walkway, as you can see in the picture, and I'd love to move it to a better spot if possible. I have no idea of the age, either.
Thanks for the link. I'll check it out!
