Lets see, I feed dandelion, plantain weed,grape leaves, mulberry leaves, violets, and opuntia pads in summer. Collard, mustard greens, turnip greens, and opuntia pads in winter. The amount of food they put away is astonding.
grass & weeds that I pull from my lawn, hibiscus flowers & leaves, various hays (timothy, bermuda... available at petstores as "rabbit food"), mazuri tortoise diet once a week (at most), grocery store greens (turnip, dandelion, etc).
My stars are actually Sri Lankans, but I feed mine:various grasses, clover greens, honeysuckle flowers, hibiscus leaves and flowers, spineless prickly pear cactus pads, dandelion greens, mazuri tortoise diet, and occasionally organic commercial spring mix.
I supplement vitamins maybe once a month or two and I sprinkle calcium a few times a week. I also leave small pieces of cuttle bone in the enclosure which they nibble at their leisure.