All herbs are mostly found in summer,they grow fresh and grow many shoots and leaves,however herbs can still grow in winter,fall,and spring.
Every herb will grow fresh in spring and will start sprouting,it is not recommended to pick them right away as they will not grow as much then. It is recommended to wait for the stems/leaves to fully grow then pick them,leave some to grow back.
In Summer all the herbs should be freshly stocked by now and it is best to gather many herbs during this time before the first frost as then most herbs will start to decay and be unusable. Many spiders will start to make cobwebs during this season for the bugs. This is a good season for battle as because most wounds shall be healed easily due to the many herbs.
In fall the herb stocks should be plentiful and you should make sure you gathered every herb you can get before the first frost. During this time the herb findings will start to get lower and lower,be prepared.
In Winter the herb stocks are probably decent and the herbs have all mostly stopped growing,you may root around brambles,covering,rocks,and more to find some remaining herbs but over 90% of herbs have stopped growing till spring,cobwebs can still be found but a little bit less common.
Almost every herb will come in batches. A shaman should be working hard in summer to gather as many herbs as possible. During winter it is also a bad idea to battle or be outside for too long because this will exhaust the vital herbs too quickly,you should also not give a feline/canine too many herbs then he needs during winter because you want to make sure all the herbs last till spring at least. If herbs run low in winter you may need to search under any areas or between any crevices for any herbs so you may last long enough.