Warm the water, honey, and dried culinary lavender in a small saucepan, maintaining a gentle simmer for 3 to 5 minutes. Look for small, steady bubbles rather than vigorous boiling.

Move the saucepan off the burner, leave the lavender to steep for 30 minutes, then strain the liquid and let it cool completely. The strained infusion should have a floral aroma without loose buds floating in it.

Place one lemon quarter and 1/4 cup blueberries in the cocktail shaker, then press them gently with a muddler. Stop when the berries have burst and released colored juice while the lemon rind remains largely intact.

Measure 4 ounces of cooled honey-lavender infusion into the shaker, add ice, and shake for 10 to 15 seconds. The shaker should feel thoroughly cold, with condensation or frost developing on the outside.

Empty the shaker into a glass, including the ice and muddled fruit. The blueberry juice should tint the liquid, with fruit pieces settling among the ice.

Slowly pour 4 ounces sparkling water into the glass and finish with a lavender sprig. Fresh bubbles should rise through the berry-colored drink without excessive foaming.

Use the remaining lemon quarters, blueberries, infusion, ice, sparkling water, and garnish to assemble three more drinks, then serve immediately. Each glass should taste cold and bright, with lively carbonation.