
Prepare pot, tools and four 125mL jars for hot-water canning.
Crush the lavender in a mortar and pestle, then combine it with the sugar.
Rinse the berries and pick them over to remove any debris.
Over medium heat, gently warm the berries until they are soft.
Add the lavender sugar to the juices in the pot and stir to dissolve.
Bring juice to a boil over high heat, and cook for another 3 minutes.
Return the berries (and any juices) to the pot and bring to a boil again.
Ladle the blueberry preserves into sterilized jars.
Process in a boiling water bath for 10 minutes.
Cool at room temperature for a full 24 hours.