Description for Grafted cactus, Moon Cactus (Yellow) Plant height: 1.2 - 2.0 inches Plant spread: 1 - 3 inches Moon cactus plants come in vibrant bright colors of hot pink, brilliant orange and even an almost neon yellow. These are small plants, generally only a half inch across, although there are cultivars that get up to 8 inches in diameter. Common name(s): Moon Cactus Flower colours: Yellow Bloom time: Spring / Summer Max reachable height: Half inch to 8 inches Difficulty to grow: Easy to grow