Add edible flower petals to ice cubes to decorate your cocktails and mocktails. To do so, fill an ice cube tray halfway with water. Freeze until the water is starting to set, about 1 hour. Top with a few petals or small flowers and cover with more water. Freeze until completely set.
Try a non-alcoholic version of this punch by replacing the elderflower liqueur with 3/4 cup (180 ml) elderflower syrup and the gin with an alcohol-free option.
The reserved rhubarb pulp can be used to top yogurt or to add to muffin batter.