How tall are 15-year-old saguaro cactus plants?

Answer 1

Common opinion is that a saguaro grows about an inch to an inch and a half a year, give or take depending on the weather. But there is tremendous variation between individual specimens. One saguaro that is 150 years old might be roughly 150" tall, or about 12 feet while another in a more sunny position or with access to more water might reach 40 feet.

Answer 2

One (1) foot (30.48 centimeters) is the height that a saguaro cactus plant (Carnegiea gigantea) may be at the age of 15 years.

Specifically, the saguaro is a slow-growing cactus plant. It may be only an inch (2.54 centimeters) high after its first year of growth. It may be 55 years old before it reaches the beginning of the expected range of its mature height: 15 - 50 feet (4.572 - 15.24 meters).