Make sure that the fireweed flowers are clean and don’t have any bugs in them.
Place the water, the sugar and the flowers in a saucepan and bring to mix, stirring occasionally.
Let the syrup boil for a few minutes, turn the heat off, add the lemon juice and cover the saucepan with a lid.
Let the fireweed syrup steep for at least 12 hours, after which you can filter it and bottle it up.
Store in the refrigerator for up to a month.
