Building a garden app taught me cultivar matters more than I realized — when do you cut YOUR catmint back?

I've been deep in perennial care data lately and one thing keeps surprising me: the *variety* changes the timing more than the species does. 'Walker's Low' catmint wants a hard shear by about half right after the first flush to rebloom; other nepeta are happier left alone. Same with reblooming daylilies vs. one-and-done.

Curious how folks here time their cutbacks — do you go by the calendar, the plant's look, or your zone's frost dates?

(Full disclosure: I built a free tool that does this per-variety + per-zone — happy to share in the comments if it's useful, but mostly I just want to compare notes.)