Fill a tall highball or hurricane glass to the brim with crushed ice.

In a cocktail shaker filled with cubed ice, combine white rum, coconut rum, pineapple juice, mango nectar, orange juice, and lime juice.

Shake vigorously for 15 seconds until the outside of the shaker is frosty.

Strain the mixture into the prepared glass over the crushed ice.

Slowly pour the grenadine down the inside edge of the glass; it will sink to the bottom creating a sunset gradient.

Garnish with a lime wheel, fresh mint, and an edible flower if desired. Serve immediately with a straw.