Result of irradiated Hudson grapefruit seed. Compared to other grapefruit varieties, Star Ruby is more difficult to grow well. It has exhibited greater susceptibility to phytophthora, nutrient deficiencies, cold temperatures, and pest problems. It does not appear to grow as vigorously as other grapefruit varieties, and the fruit is often smaller. Nevertheless, when grown well, Star Ruby produces attractive red-blushed fruits with a smooth yellow rind. The flesh is very darkly-pigmented, juicy, and low-seeded or seedless. Star Ruby’s season of maturity is mid to late-season, and the fruit holds well on the tree with some loss of flesh color as the season progresses.