Characteristics of a Saguaro Cactus

Habitat Characteristics

• Saguaro only grows in a small portion of the world --- the lower Sonoran desert from northern Arizona, along the Colorado River to California's Riverside and Imperial counties, and down to northern Sonora in Mexico. It thrives in well-drained soil and full sun but can't live through prolonged freezing temperatures. That is why the saguaro only grows in certain areas of the Sonoran desert. The majority grows between sea level and 4,000 feet in elevation. The few saguaros found above 4,000 feet live on south-facing slopes. Freezing temperatures are less frequent and last for a shorter period in these pockets.

Growth Characteristics

• The saguaro grows just 1 to 1-1/2 inches in the first 8 years of life. Saguaros grow under nurse trees like mesquite and ironwood. Saguaro kills their nurse trees because they aggressively take water and nutrients. The plant's branches don't appear until it's 50 to 75 years old. In low precipitation areas, it may be as long as 100 years. It begins producing flowers at 35 years of age or so. The average adult saguaro is 125 years old. Most live between 150 and 175 years, with some reaching 200 years and even older.

Physical Appearance

• Young saguaro is hard to see because they're often hidden under a nurse tree. The long, narrow cactus has only one trunk until it sprouts branches looking like u-shaped arms reaching upwards. An adult saguaro weighs six tons or more and is 50 feet tall. Saguaros have pleats accounting for expansion during a heavy rainfall, when the store large amounts of water. They have woody, ribbed skeletons inside supporting its water weight.

Reproductive Characteristics

• Flower buds appear in the middle of April at the top of the main cane and arms if the cactus is old enough to produce. Flowers open at night and close during the day. Bats, insects and birds pollinate the flowers. A pollinated flower takes 30 to 40 days to turn into ripe, red fruit. The fruit splits open, and dessert animals consume the sweet flesh and more than 2,000 small, black seeds. A seed may end up germinating, starting the lifecycle again. The best location is one with a larger shade plant or nurse tree that also gives additional moisture.