1 medium watermelon, divided (half for 1 1/2 cups juice, half for serving)
¼ cup vodka
2 cups sauvignon blanc
Mint, for serving
Directions
In a small bowl or large pitcher, combine the blackberries, peaches, sugar, and Grand Marnier, stirring to coat the fruit as much as possible. Let rest for 30 minutes; fruit will release some liquid as they macerate.
Blend 3 cups of watermelon into a liquid. Strain the watermelon juice in a fine mesh strainer to remove seeds and pulp.
Place fruit and their liquid in a pitcher and cover with 1 ½ cups watermelon juice. Add the vodka and sauvignon blanc and stir. If desired, let rest for 1 hour to let the flavors develop.
To serve, scoop remaining watermelon half into balls with a melon baller and add them to glasses. Add ice, then pour sangria over ice. Garnish with mint and the sangria's fruit, along with edible flowers, if desired.