There are some types of prickly pear that are definitely hardy in zone 5. I have a prickly pear that's growing in my back yard that I have NO idea on how it got here. Last year it wasn't there. This year, it's about 3' tall w/about 10 paddles. Definitely don't want it, so I gotta dig it up. I hate cacti.. I backed up into one when I was a kid & got spines in my thighs & butt pretty badly. Super bad thing was that I had a 1.5 hour bus ride home (we were at a school field trip) and so I stood the entire time. Then my mom, giggling the entire time, had to spend like an hour pulling spines outta my butt and legs and then dousing me in hydrogen peroxide, which burns me pretty badly. Thereafter: no more cacti for me for ANY reason.
A couple of years ago I bought a "hummingbird mint" (agastache) that the tag stated that it got to be 18" tall & 18" wide. So I put in an area that gave it a 2' radius. Damned thing grew to be over 4' tall and about 5' wide in less than a year. Took over half of my mini-rose bed. TAGS LIE.
