Short internodes, profuse branching, and a compact habit of growth characterize this cultivar. The medium-sized, seedless fruit have exceptional red flesh color and a distinctively smooth, thin peel with a pronounced red blush. Flesh is firm, uniform in color, and of excellent quality. Furthermore, juice is deeply colored even late in the season and may enhance 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. Propagation of 'Star Ruby' in Florida peaked during the 1984-85 season and has since declined, presumably because of cultural problems associated with this cultivar. Thompson, ' aka 'Pink Marsh,' arose as a limb sport of 'Marsh' near Oneco, Florida. In 1924, 'Thompson' was introduced by a local nursery and, being the first pigmented seedless grapefruit cultivar, became quite popular. Fruit characteristics are essentially identical to 'Marsh,' except the pink flesh color.