Eupatorium perfoliatum: seeds

Eupatorium perfoliatum, known in English as common boneset, thoroughwort, feverwort, or agueweed, and in French as eupatoire perfoliée, is a perennial native to most of eastern and central North America. It bears umbels of fluffy white flowers.

This is my first attempt at growing boneset. I bought these seeds from the North American Native Plant Society at Seedy Saturday. I am cold-moist stratifying them in the fridge to simulate a North American winter.