Rhodes grass is a subtropical grass which means it can’t store large amounts of starch or water soluble carbohydrates (WSC).
Rhodes grass will usually have a starch + WSC content (known together as the non-structural carbohydrates, or NSC) of less than 12% making it consistently safe to feed to horses that need a low NSC diet. Including laminitic horses and ponies.
Rhodes grass hay is usually a moderate protein, moderate calorie hay (depending on its stage of growth when it was harvested) so it lends itself well to being the base hay in almost any horse’s diet.