Loose I'm not sure, but the Indian Market in Norton MA (in the old Roche Bros) has a huge tea aisle with some pretty sizeable boxes from all over the world, and two aisles for nothing but herbs and spices.
I'm assuming you're not talking about weed because it's legal now and you wouldn't have to hide it.
If you don't mind ordering online, Upton Tea. They are based in MA so sort of local still. Large selection and great customer service. I have zero affiliation with them.
TimeSlipperWHOOPS t1_j3988yx wrote
We get our loose tea from Sanctuary farms, they might sell larger packages