Make chamomile honey syrup: Put honey, 1/4 cup water, and tea in a small pot over low heat until hot, but not boiling, about 2 minutes. Stir, remove from heat, and let sit 1 hour. Strain and cool.
Meanwhile, with a Y-type vegetable peeler, remove a long strip of zest from the grapefruit’s circumference; repeat. Roll each into a tight coil, then push up from bottom to create a bud; skewer through middle with a cocktail pick.
Juice grapefruit to yield 2 oz. juice. Pour into a cocktail shaker with 1/4 to 1/2 oz. chamomile honey syrup and vodka. Add ice; shake well. Add sparkling wine.
Set zest flowers in coupe glasses. Cover shaker and strain cocktail into glasses.
*Creamy, pearl-white kiawe honey is produced from the flowers of Hawaii’s kiawe tree, a type of mesquite (from $7.50; for an 8-oz. jar; rarehawaiianhoney.com).