Rust, undoubtedly.
Rust on one of my baby seedlings!
In line with that, I submit
resistant. We should all be hybridizing with an eye to increasing
rust resistance in our seedlings, and hopefully in our collective gene pool.
Others have covered
rebloom, so I guess that leaves me with
recurved.
Per the AHS:
Term used to describe a blossom's appearance. Petals reflex back toward the base, giving a rounded ball-like appearance.
Recurved daylilies have high value for me, since they tend to open better in our climate. Even after a cool night, they will at least open flat.
When you think about it, many of the UFs are also essentially
recurved. While I prefer ruffles in my daylilies, more and more UFs have been finding a home here, simply because the blooms reliably open well.