ANNUAL. Used to dye umeboshi (a salty pickled plum condiment popular in Japan) red. A beautiful and refreshing drink can be made from the leaves: Bring 1 liter of water to a boil and add 5 handfuls of leaves. Turn off heat and let steep for a couple minutes. Then stir in 1 cup of apple cider vinegar or lemon juice and you'll see the science laboratory magic of the acids reacting with the shiso to turn the water pink, pink, pink. Add sweetener to taste, strain out the leaves and chill.