Combine rum, strawberry rhubarb simple syrup and lime juice in a shaker with ice. Shake vigourously. Strain into a glass filled with ice.
Strawberry Rhubarb Simple Syrup
To make the simple syrup combine all the syrup ingredients in a sauce pan over medium-high heat. Bring to a boil, then reduce heat and let simmer for 20 minutes.
Place a fine mesh strainer over a bowl or a jar; pour the mixture through the strainer. Use a spoon to press any remaining juice into the container. Let cool before using. Keep any extras refrigerated.