The medium-sized, seedless fruit have exceptional red flesh color and a distinctively smooth, thin peel with a pronounced red blush. Sugar and acid content are higher than that of 'Redblush'. Flesh is firm, uniform in color, and of excellent quality. Furthermore, juice is deeply colored, even late in the season and may have potential for enhancing the color of pink grapefruit juice. However, 'Star Ruby' is more difficult to grow in Florida than most other grapefruit cultivars.
Foliage is often chlorotic.
Trees are easily damaged by some herbicides and are susceptible to foot rot. In 1924, 'Thompson' was introduced by a local nursery and, being the first pigmented seedless grapefruit cultivar, became quite popular. However, other seedless cultivars with superior flesh and peel color were soon discovered and planted in favor of 'Thompson'. Fruit characteristics are essentially identical to 'Marsh' with the exception of the pink flesh color. Fruit hold well on the tree, but flesh color fades as the season progresses.