The main mod, modAllHerbRespawn, adds a missing 1440s (real-time) respawn timer to Fool's Parsley, Hornwort, Longrube, and BaW Clovers.
Without this timer, these herbs failed to "grow back' after picking.

PLEASE NOTE:
The main mod is included in the legacy (1.31/1.32) version of
Brothers In Arms - TW3 Ultimate Bug Fix Collaboration https://www.nexusmods.com/witcher3/mods/5752
All Next Gen versions of the game also include this fix.

All credit goes to paulr0013, and especially MerseyRockoff, who guided me to find this bug fix solution.

I have also added Optional files for the following:
modAllHerbs24HourRespawn, with a 86400s (24 real-time hours) respawn time for all herbs. Special request from Skylog.
modAllHerbs24HourRespawnNextGen for Next Gen game versions
modAllHerbs2HourRespawn, with a 7200s (2 real-time hours) respawn time for all herbs. Special request from NeighbourhoodGigolo.
modAllHerbs2HourRespawnNextGen for Next Gen game versions
modAllHerbs5HourRespawn, with a 18000s (5 real-time hours) respawn time for all herbs. Special request from NeighbourhoodGigolo.
modAllHerbs5HourRespawnNextGen for Next Gen game versions
modHerbNoRespawn is intended to stop all herbs from respawning. Special request from Deepk. Version 1.1 includes .xml files with deleted timers. Version 1.0 (in Old Files) does not include these .xml files. Both versions have been confirmed to be effective in stopping all herbs from respawning though.
modHerbNoRespawnNextGen for Next Gen game versions

Please note: All these timers are real-time in-game timers and are therefore unaffected by meditation time.

Installation:
Simply download the mod and add it to your 'The Witcher 3\Mods' folder.

Uninstallation:
Delete the mod from your 'The Witcher 3\Mods' folder.

And don't forget to endorse! ;-)