Star Ruby Red Grapefruit tree grapefruits are slightly flat, round sized fruits with yellowish-orangish rinds and a sweet, tart flavor taste. They have a yellow-orange skin and a pink to reddish-pink flesh. When planting this particular citrius tree, make sure it is planted in an area where it will receive 8-12 hours of sunlight daily. Expect your Star Ruby Red Grapefruit tree's fruit to ripen anywhere between mid June and early October. (USDA Zones 9-11b)