There will be a variety of custom plants to find in Epoch Mod, currently there are: poppies, goldenseal root, and pumpkins.
Poppies don't have any real benefit- when you consume this plant your stamina is decreased and your fatigue shoots up. It's a "recreational" plant.
Goldenseal Root will reduce your toxicity a small amount.
Pumpkins will give you a boost in your hunger stat by +500.