The easiest way to get herb teas is just drying up the leaves and flowers you plan to use. This summer I thought I'd learn a new method of finding some new tastes from familiar plants by fermenting. This is how green tea turns into black tea.
The leaves in the photo are from a rowan tree. I also mixed some bilberry and fireweed (which is by the way an excellent basis for any tee mixture) leaves with it. Other plants more than appropriate here include for example raspberry, black currant and birch.
When the leaves you plan to use are still fresh, crush them (between your hands or using a rolling pin for example) so they juice up evenly. Lay them fluffily in a large glass jar and cover. The process needs some oxygen so see the lid isn't too tight.
Place the jar in a hot place (40-50°C) for as long as the leaves have turned brown. You can for example cover the jar with a black t-shirt and leave it on a window sill on a hot summer day or put it in a polystyrene box with hot water bottles. Depending on the plant this may take only an hour (as in the case of rowan) or several days. Last, make sure the leaves have dried up as well so they won't mildew. (I spread them on a newspaper for a night.)
The aroma lasts longer if you store the leaves intact and crush them only a moment before usage.