I processed the blueberries I picked a few weeks ago with lavender [and vanilla] using this recipe from Serious Eats, and I split the batch with a friend who bought the jars and supplied the sugar and the kitchen. I was initially concerned about what the lavender would taste like in the jam, but it isn't overpowering; it's just a little "hmm, what could that be?" that is loverly. We added the vanilla for the second go round, one tablespoonish.
We came out with 8 jars a batch as specified by the recipe, and it's low in sugar. Which is great, since everything else in presently packed in my cellar will send you into diabetic shock... I'm only half kidding.
What I discovered about living in the city is that one cannot procure 4 ounce jars for love or money, from anyone. And for reference, four ounce is the one that says blueberry lime jam on the lid - it's the tiny short one. The two in the middle are eight ounce jars [one is labeled and the other is filled with Apricot Peach Mango goodness]. The one in the back is a 12 ounce square-ish side jar. That one is tutti-fruity mash up. I digress: 4 ounce jars can't be found in the city unless they are from Italy, in which case they cost an absurd amount of money and can only be bought one at a time. This, I feel, is insane. The next time I go picking berries out afield, I'll try to stop at the local hardware or big box store and pick up a flat of tiny jelly jars. Down side of city life : not everything your little heart desires is available, contrary to popular claims. I did find wide mouth pints, which are short like the 4 ounce, but are obviously bigger. Cost prohibitive. Also not what I was looking for.
Because I ran short on fabric for a project and will have to get some more for that one, I was thinking that, since I am planning on giving this as gifts anyway. it might be fun to find fruit fabrics with the type of fruit featured in the jam or jelly. Since I'll be out there looking anyway...