This large cactus shrub spreads out wide before growing tall, adding color to an outdoor garden. It has large, green pads with purple stems. When happily stressed, the pads can turn a purple color, too. Watch for reddish flowers in the Spring.Opuntia macrocentra “Black-spined Pricklypear” is an excellent rock gardens and xeriscaped yards. It is deer-resistant, and its flowers attract hummingbirds.