Will the Saguaro cactus grow in Missouri?

It most likely won't grow outdoors in Missouri. It may grow indoors. A saguaro cactus [Carnegiea gigantea] isn't native to Missouri. It prefers a desert environment of high heat and light, and low moisture and vegetative competition. In terms of the outdoors, a saguaro cactus most likely won't like the eastern part of the state, which tends to have humid growing seasons. It may be able to tolerate the western part of Missouri, which tends to fit in with the drier, hotter growing seasons of the Great Plains. But no matter the part of the state, a saguaro cactus most likely won't like Missouri winters, which tend to bring the cold, damp weather that desert cactus plants detest.