In a medium saucepan, bring sugar, rose petals, and water to a boil. Stir occasionally. Reduce the heat and simmer the mixture for 20 minutes or until the mixture starts thickening.
Strain the syrup into a clean bottle. Allow the syrup to reach room temperature.
Pour 2 tablespoons of rose petal syrup in a glass. Add milk and ice. Stir.
Using a handheld milk frother, froth a portion of oat milk and pour on top of the drink. Garnish with rose flower petals.