Hi, Pax. It looks like you have some kind of Multiflora rambler. Until it blooms, I can't help with further ID. If you post photos when it blooms next spring, there's a good chance of IDing your rose on the forum. Carol

What Carol said. Let it grow - old roses sometimes take a while to start blooming - they wait until they decide they are a "proper" size or height first. So, whatever you do, don't prune it - just let it be, make sure to give it enough water, and next Spring post pictures of the blooms on here, including buds and fully opened blooms, and someone will be able to ID it. When you found it at the abandoned home site, did you root it, so what you have is a rooted cutting?

Jackie

It had many stalks running across the ground, many of which had rerouted, so I dug up one of those, which had roots, and repotted it. I dipped it in superthrive before potting. Any other tips for transplanting new runners?

You won't see flowers until it has stems big and old enough to bloom. Once it has sized up a little the pattern that should emerge is new canes starting to flower their second year. When trained on structures and given intensive pruning regimes the convention is pruning out canes that have flowered, tying in the new ones every year.

Same as with June bearing raspberry plants - although the flowered growths of ramblers do not seem to deteriorate as markedly and rapidly as those of raspberry plants.

Pax - it looks as if whatever you did, it worked fabulously. Congrats! Can't wait to see the flowers next year.

Jackie