How long does it take for flowers to respawn?

[TK Darkhaven]

I'm trying to farm Hubflowers but I waited 72 in game hours at Diamond City then fast traveled to the road where I picked them, and they haven't respawned.

[Gamefever]

I think that it actually requires....
Actual Game time spent playing....A lot of things do for instance the stuff found in settlement Workbenches require that the game has had actual real world time spent...With the game running.

[casualsailor]

It is a lot longer than 3 days. And like masterpainter said you can't just wait or sleep you must actually play.

I don't know but I suspect it is tied to the respawn rate for other things. On Normal that is 7 to 20 days and Survival it is 35 to 80 days.

[Gamefever]

Rather than trying to farm just one spot,
There are quite a lot of Area's to get Hubflower.
Pretty much everywhere you go around the Starter Area of the Vault, Abernathy Farm, and Tenpines Bluff. Those three area's and everywhere between you will be tripping over Hubflowers like weeds in the vegatable garden.

For the most part though Hubflower tends to be found away from cities and near to less populated area's but basically North side of the map has a lot of it too be found.