In Russia, rosebay willowherb (fireweed) leaves are fermented in to a lovely tea. It is an old tradition, and before chinese tea was readily available in Europe, Russia exported huge amounts of Ivan Chai to western Europe. In russian it is known as Koporskij chai (Копорский чай) or Ivan chai (иван-чай), but Ivan chai is also the russian name for rosebay willowherb, as found growing in the wood. Leaves are picked both before and during flowering.
Rosebay willowherb often grow in large groups in clearings in the forest or wood. It is quite common in my area. You can start to harvest as soon as you recognize the plants, and you can continue during flowering until seeds are formed. Seed fluff in your tea is not pleasant.
A harvest tip: Grab the stem below the inflorescence. With the other hand slide down the stem, collecting all the leaves while doing so. This way you can harvest what you need for a year in an instant.
The leaves must undergo a fermentation process to bring out the good flavor. The flowers can be dried without fermentation and mixed in as decoration.
Russia is a huge country, and similarly there are many opinions on how best to ferment and dry Ivan chai.
I chose to squeeze the leaves until the got soggy from their own juice, tucked them firmly in a polythene bag and let them ferment for two days. I’m using longer fermentation than russian sources prescribe, as my summer temperatures are considerably lower, and I don’t want to use artificial heating during the fermentation process.
After fermentation I cut the leaves into narrow strips and dry them.
Preparing the tea for drinking, I use about double of black chinese tea. But then I can prepare a nice tea two to three times from the same Ivan chai leaves, before the taste deteriorates.
The taste is lovely, a bit like a cross between black and green Chinese tea. Contrary to Chinese tea, Ivan Chai is slightly sedative.