8 Facts About Saguaro Cactus

Saguaro cactus

Like other members of the columnar cactus family, the saguaro is a large, tall green plant with a stout trunk topped by several broad pads that get wider as they ascend. The saguaro’s branches grow upward and outward from the apex which is called the crown. These can spread out as much as 10 feet (3 meters) on a side and can be seen from up to 20 miles (32 km) away in ideal conditions. A branching factor of 1 – 2 inches per year is considered normal for most healthy plants, though wide-ranging or vigorous plants may grow at rates up to 1 foot per year (30 cm). The saguaro cactus grows 15 to 30 feet (5-9 meters) per year on average in height, width and girth, until maturity is reached.

Saguaros are unusually efficient at absorbing water from the soil, as their root system extends much deeper than that of other plants. The trunk’s vascular system is capable of storing water. In addition to these adaptations to a dry climate, the saguaro blossom is pollinated by nocturnal moths, which also lay their eggs on the plant’s sweet red fruits which resemble large red pineapples by day. Saguaros have deep tap roots up from which new growth emerges. They can live for more than 100 years. The distinctive saguaro form is largely a product of evolution being acted on over thousands of years by variations in available sunlight, water, and nutrients.

The saguaro typically grows up to 40 feet (12 meters) in height. The massive arms develop from the main stem and branches with age. Saguaros grow extremely slowly from seed, with plantings taking at least 7 years to mature and produce their first flower. Growth is fastest during the first year after emergence from the seed, with a month between each growth ring. After this they grow one inch to 1½ inches per year until around 50 years old and growing only very slowly after 75 to 90 years.

Habitat

The saguaro inhabits the Sonoran Desert in Arizona and Mexico. It grows best in areas with ample summer rainfall and low-intensity summer sunshine, such as provided by desert scrub, yucca groves, the edges of washes, and grassland. The specific epithet “schottii” commemorates botanist Charles Frederick Schott (1888 – 1958).

Taxonomy

The saguaro is classified as a member of the Carnegiea genus of cacti in the Cactaceae family. It is native to a small area of northern Sonora (state) in northwestern Mexico; it also grows into adjacent southern Arizona. Saguaros grow best here within U.S. state of Arizona when provided full sun with a minimum temperature of 40 °F (4 °C), well-drained soil, and occasional deep watering. They usually are protected from high winds by surrounding terrain. They are commonly found in the mountains at elevations between 1,200 and 4,000 feet (350–1,200 meters).

Saguaros grow slowly from seed, so the normally observed increase in size is due to growth of extensions called arms that form around the base. Although they may live for over a hundred years, saguaros grow slowly and typically live up to 75 years. They exhibit allometric growth: tissue grows disproportionately faster in diameter than it does in length. This causes the arms to grow faster than the trunk, uncoiling from the base.

In the Arizona desert, saguaros usually grow only from April through October, with peak growth during June and July in most years. The larger rainfall in autumn and winter is often insufficient for significant growth, as well as being a period of dormancy for most cacti. Saguaros typically begin activities again in February or March of the next spring.

Saguaros are so distinctive that they are easily recognized by non-flowering plants.

The saguaro cactus, the largest species of cactus in the U.S., can grow up to 40 feet tall

The saguaro cactus is the largest species of cactus in the U.S., and one of the largest in the world. Standing fifteen to forty feet tall, they have a distinctive shape and can live for 150-200 years. These giant plants are native only to Arizona; you can’t find them anywhere else in America!

The saguaro is more than just a plant, it’s an icon – cherished by locals and visitors alike for its height, strength, beauty, and undeniable presence. Tourists from all over the world flock to Arizona every year specifically to see these graceful giants grow near Tucson, Phoenix, and Saguaro National Park on their way westward to California or Nevada.

Saguaro cacti are enormous. They can weigh up to 1 ton

Water makes up 90% of a saguaro’s body weight, so it is important for these plants to stay hydrated or they will die quickly, even though they are native to the desert. They have branches that extend upward from their bodies to form a canopy of needles, making them look like green trees.

The saguaro is extremely well-adapted to make the most of every drop of rain

The saguaro cactus thrives in the driest of desert environments, making the most of every water droplet and has developed a canopy-like crown, which catches precipitation and retains it for eventual transpiration.

But water isn’t captured passively – there are spikes on the crown that are arranged to collect water from even the smallest droplets. As rain flows over these spines it falls down their channels into reservoirs below, where it accumulates in natural depressions that form at the base of each spine head. When these reservoirs become full enough, they release their precious liquid so as not to overflow onto surrounding tissues with potentially damaging results.

In Arizona, it is illegal to harm a saguaro cactus

Arizona law section §13-3101 prohibits injuring, breaking, cutting, pulling or trampling down a cactus. Violating this law is punishable with a misdemeanor.

The saguaro cactus is the largest in North America and it’s protected because it’s both a state and federal threatened species due to poaching and development. Additionally, the saguaro fruits are the main food source for deer mice which are also considered threatened species in Arizona. The saguaro cactus’s soft, white inside is also used for food by many bird species.

The Cactus Protection Act was passed in 1987 to protect the saguaro cactus and introduced fines for anyone who damages or vandalizes a saguaro. In 1994, the law was updated to include trampling as a violation and included a $500 fine.

In 1974, the Arizona Game & Fish Department raised awareness of poaching and began protecting 18,000 acres of land around Tucson. The Department also built fences around the area to protect the cacti from poachers. It’s now illegal to pick any wildflowers or plants that grow within those protected areas.

Because of invasive species like buffelgrass, the saguaro cactus is in danger

The threats facing this species include introduced species like buffelgrass (herbaceous plant native to Africa that has been found to be a particularly aggressive invader). The density of buffelgrass greatly impacts how easily and quickly these plants take over native flora which causes a restriction on their natural resources (e.g., water) and can damage habitat for animals that depend on them as food sources. With the increase in the density of buffelgrass, the saguaro has less access to water.

Saguaros blossom in spring and summer

The blooming season is a dim two-week affair, but in that time one of the desert’s most famous residents puts on an amazing display.

There are many different types of Saguaros and they all have their own traits; however, they will bloom for a short period of time in late spring or early summer depending on the species, primarily around June and July. The blooming season is a very short affair lasting only two weeks; however it is truly one of nature’s amazing sights to see! These plants let loose with flowers like mini fireworks displays during this brief period. The flowers are actually nothing more than a big bundle of stamens and stigma and each flower will produce a small berry.

Saguaro cacti are ideal for birds that nest in them, such as woodpeckers

What many people do not know about these trees is that they serve as nest for birds such as Gila woodpeckers. The Gila Woodpecker lives in the Sonoran Desert and can be found nesting on saguaros year-round. These birds actually make their homes inside of the cactuses, which may be surprising to people who have never seen one. The birds drill holes into the side and back of saguaros to make their nests. They prefer these trees because they see them as being a safe location for raising their young. After all, the trees provide protection from predators as well as a way for them to hide from other larger animals in the area.

To get into the saguaro, the woodpecker drills holes directly through the skin of the cactus. You can see where you might get pierced by one of these holes if you look closely, but you will not feel a thing if you do get pierced! The woodpeckers use this technique as a way to determine whether or not a saguaro is healthy and fit for family life. If one is not strong enough to provide protection from predators, it will be turned away.

The cactus itself actually provides protection from rain and wind in addition to housing small creatures like bees and ants that can provide food for them while they are living in the tree.

The scientific name of saguaro is Carnegiea gigantea

The saguaro’s scientific name, Carnegiea gigantea, is given in honor of Andrew Carnegie. In 1901 Carnegie had established a desert research station in Tucson, Arizona under the auspices of one of his philanthropic organizations. With the help of this lab, many new species of cacti were discovered as well as the propagation and knowledge on how to care for these desert plants. It was a tough task to find a name that could honor all that he had done and that one fit him so well; however, it is not uncommon to find some people calling this giant cactus “Carnegie’s Tree” or simply “Carnegie Cactus” in parts of Arizona.