The giant sequoia (Sequoiadendron giganteum), one of the world’s tallest and most limited plants in terms of natural habitat, likely won’t do well in most areas of the Midwest, including Iowa. Because it is adapted to such a small range, it is best grown in climates that mirror exactly its habitat of origin.
Though sometimes referred to as giant redwood and big tree, the giant sequoia is also infrequently referred to as the Sierra redwood, for its mountain range of origin. It is a fine-textured, densely growing evergreen tree capable of reaching heights of 250 to 300 feet in the wild. In home cultivation, it generally doesn’t grow taller than 60 to 75 feet, with an eventual canopy spread of between 25 and 30 feet. Attractive foliage is bluish-green and its spongy-looking bark is orange-red. Giant sequoia is often temperamental, and can grow poorly outside its native range.
The giant sequoia has an extremely small natural habitat, growing on the western slopes of the Sierra Nevada mountain range, exclusively in the state of California. This very small belt is about 260 miles long and 15 miles wide, or less, containing within it pockets of giant sequoia trees. The tree generally grows at elevation, the lowest natural occurrence at 2,720 feet and the highest 8,860 feet. At the southern end of its natural range, it grows mostly on north-facing slopes.
Because of its natural environment and adapted tolerances, it is very unlikely the giant sequoia will thrive in Iowa. Iowa is a climate of extreme temperatures, ranging from quite cold in the wintertime to very hot in the summer. Its U.S. Department of Agriculture hardiness zone ranges from 4b on the northern end and 5b on the southern end, with extremely small, scattered pockets of USDA zone 6a. In these small areas, giant sequoia might grow, but climatic swings in both summer and winter will likely upset the plant and it won’t do well. Iowa also doesn’t offer the elevation ranges that giant sequoia grows at in the wild.
Giant sequoias prefer cool, moist climates that mimic their native Sierra Nevada home. They prefer sunlight and well-drained, loose, sandy loams. Although they prefer consistent moisture, they are also drought-tolerant once established. They require very large spaces in which to grow. Attempts to cultivate them beyond their comfort zone will likely end in disappointment.