Star Ruby Grapefruit Tree

Star Ruby is a red-fleshed grapefruit selection with very dark flesh and few seeds. The evergreen tree needs a long, warm growing season and a protected site because grapefruit is sensitive to frost. ## Selection and size The [Givaudan Citrus Variety Collection at UC Riverside](https://citrusvariety.ucr.edu/crc3770) identifies Star Ruby as Citrus paradisi and describes its dark red, low-seeded fruit; it also notes that this selection can be difficult to grow and is especially cold-sensitive. The exact [Star Ruby product profile at Trees.com](https://www.trees.com/products/star-ruby-grapefruit-tree) lists 15–20 feet mature height and 12–15 feet width, matching the ranges shown here. [Texas A&M AgriLife](https://aggie-horticulture.tamu.edu/fruit-nut/fact-sheets/citrus/table-1-common-texas-citrus-varieties/) also lists Star Ruby among common Texas grapefruit varieties. ## Siting and fruit Grow outdoors in USDA zones 9–11, in full sun and well-drained soil. The [Four Winds Growers Star Ruby profile](https://www.fourwindsgrowers.com/products/star-ruby-grapefruit-tree) lists the same outdoor zones and recommends protecting citrus below freezing. A container can be moved into a bright sheltered place in cold weather, though warm summers support good fruit quality. UCR reports a February–June ripening season for its Riverside collection. ## Maintenance Water deeply during establishment and extended dry weather, allowing the root zone to drain. Apply citrus fertilizer according to its label, and prune lightly to remove damaged branches or control access. Protect the canopy from frost and avoid saturated soil.