Red Grapefruit (cultivars include ‘Ruby Red’ or ‘Star Ruby’) is a vigorous, spreading, evergreen citrus tree. It is highly valued for its large, round, thick-skinned fruit, which features a distinctively sweet, low-acid flavour profile compared to traditional white grapefruit. The flesh ranges from a deep pink to a vibrant ruby-red colour. The tree has large, glossy, dark green leaves and produces highly fragrant white blossoms, typically in spring, followed by a winter harvest. It is a subtropical plant, thriving in warm, humid to temperate areas, and it makes a beautiful, structural feature tree in the home garden.
Care Tips:
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Position: Requires a position in full sun (at least 6-8 hours of direct sun daily) to ensure heavy flowering and optimal fruit development and sweetness.
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Climate: Best suited to subtropical and warm temperate climates. Mature trees can handle light frost, but young trees need protection.
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Soil: Plant in deep, fertile, well-drained soil. Like all citrus, it dislikes heavy clay or waterlogged conditions, which can lead to root rot.
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Watering: Water regularly and deeply, especially when the tree is flowering and the fruit is swelling. Consistent watering is crucial for producing large, juicy fruit. Mulch well to maintain soil moisture, keeping mulch away from the trunk.
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Fertilising: Citrus are heavy feeders. Use a slow-release fertiliser specifically formulated for citrus (high in nitrogen and potassium) in early spring, mid-summer, and early autumn.
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Pruning: Prune lightly to shape the tree and remove dead or crossing branches. Pruning is usually done after the harvest. Unlike some fruit trees, grapefruit do not need heavy annual pruning.
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Harvest: Fruit ripens in late winter to early spring in Australia. They hold well on the tree, allowing for a long harvest window.
