I have harvested and made tea from my own burdock and dandelion roots.

The taste and appearance of the tea is completely different from if I use dried roots purchased from the US or the UK (but both the US and UK roots taste the same).

The tea made from the online roots is much darker and has a stronger flavour, almost sweet in the case of burdock. My tea from freshly harvested and dried roots have a more grassy flavour and is a lighter, somewhat green colour.

I have triple confirmed that the roots I harvest and dry myself are definitely dandelion and burdock roots.

The only thing that I can think of that would cause such a difference is the drying time. I dry my roots for a couple of weeks before making a tea out of them. Perhaps the roots I buy online are dried for much longer?

What could be causing such a difference?

I use about 50g of each in my teas, this gives me three good sized mug fulls for the day.