When I retired and started to develop a list of places to experience, Saguaro National Park was an early entry. Since my days of watching western movies I have always been intrigued by the unique shapes of Saguaro cacti. We scheduled our visit for late winter, as March and April are wildflower season in the Sonoran Desert of Southern Arizona and the moderate temperatures would be great for hiking.

Saguaro National Park is comprised of two districts – the Rincon Mountain District ,or East, and the Tucson Mountain District, or West, which lie about 35 miles apart.

Our introduction to Saguaro East was going to be a scenic drive. We have had outstanding experiences with the official scenic drives in the National Parks that we have visited, so we were certainly interested in driving this route. The photographer was out of her walking boot but we were proceeding cautiously with trail terrain and walking surface selection.

After a short visit to the Rincon Welcome Center at the gate of Saguaro East, we queued up in our rental car, with the rest of the visitors, to enter the park itself. The Scenic Drive is a one-way, 8 mile loop road with numerous pull offs that allow for the more hurried travelers to pass and proceed at their own pace.

But the pull offs also allowed us curious amateur naturalists the opportunity to exit our vehicles to inspect roadside plants up close and to take in the outstanding vistas. There were also small parking areas at several trailheads that allowed deeper entry into the desert landscape. The speed limit on the route is 15 miles per hour, so conceivably one could complete it in 30 minutes – it took us over five and one half hours, including a picnic lunch and a one hour hike on the Cactus Forest Trail.

Cactus Loop Drive was originally developed by the Civilian Conservation Corp (CCC) from 1936 to1938, during the Depression, when the site was named Saguaro National Monument. Amazingly, other than surfacing with asphalt in the 1950s and widening for a bike lane in the 1990s, little has changed in the almost 90 years. Some of the original retaining walls could be appreciated along the route.

It was designed with overlooks and turnouts to allow the visitor to take in the unique beauty of the Sonoran Desert.

As one works their way around the loop in a clockwise direction, one notes that the expanding suburbs of Tucson, Arizona have encroached on the park on the western and northern boundaries. The Catalina Mountains to the north are outside the park but provide a beautiful backdrop behind Tucson homes in the photo below.

But the Rincon Mountains to the East are within the park and have a more intimate effect. The botany transitions from desert plants in the valleys, to oaks on the slopes, and then Ponderosa PIne and Douglas Fir in the higher altitudes.

The slopes at the base of the Rincon Mountains, regionally referred to as Bajadas, were largely bare surface stone.

One of the more obvious features in the Sonoran Desert in general, and Saguaro National Park in particular, are the presence of dry creek beds that are named “washes”. They are bone dry for most of the year, except for the two rainy seasons. In late winter there can be days long steady rains that, with run off from the rocky surface of the valleys, can lead to water in the stream beds. Late summer, however, features torrential rains, that can dump up to 2 inches per hour, which can fill the washes with flash floods. Where a road crosses a wash there will be signs warning of the dangers of crossing the stream. The leafless trees alongside the washes in the photos below are Mesquite and Palo Verde.

At many of the pull offs there were information boards that presented items on the history and ecology of the parkland. Being unfamiliar with the Sonoran Desert ecosystem, these were very helpful to us.

As was outlined on the above plaque, the movement to protect the Saguaro Forest began in 1928 when Homer Shantz, the president of the University of Arizona, expressed concern for the loss of the ecosystem by the expanding city of Tucson. In 1933 President Herbert Hoover designated this site Saguaro National Monument, and in 1961 President John F. Kennedy added the Western District on the west side of Tucson, to protect additional land. But the designation did not fully protect the fragile ecosystem. In 1937, and again in 1962, freezing temperatures lead to the death of significant numbers of Saguaros. Greater concern arose when it was noted that there were very few juvenile cacti to replace them. This was due to the fact that despite the site being a National Monument, open cattle grazing was still allowed on the acreage, which resulted in destruction of young cacti, as well as the Mesquite and Palo Verde trees that play a critical role in the Saguaro lifecycle. In 1979 cattle grazing was finally prohibited and the ecological recovery began. In 1994 both areas were designated Saguaro National Park.

Undoubtedly the stately Saguaro (pronounced “suh·waa·row”) is the icon of the Saguaro National Park and the Sonoran Desert itself.

Due to competition for water the Saguaro, like most desert flora, are evenly spaced across the terrain.

It is rare to find specimens in close proximity to each other, but we did on this occasion.

The lifecycle of the Saguaro is fascinating. The cacti flower in evenings in late spring and are pollinated by two species of bats who feed at night, as well as White-winged Doves and insects during the morning, before the flowers close in the afternoon sun. About two thousand seeds develop in an egg shaped fruit that is about two and a half inches by one and a half inches. The fruit ripens in June and July, and are consumed by many animals, especially birds. The seeds pass through the animals and are deposited with fecal material, frequently in the shade of the Mesquite and Palo Verde trees. These trees provide an element of protection for the small cacti, shielding them from temperature extremes and direct sunlight, buying them time to develop their root systems in this harsh environment. The Mesquite and Palo Verde are termed “Nurse Trees” for the Saguaros. It was the loss of the nurse trees, as well as direct trampling by the grazing cattle, that led to the lack of juvenile Saguaros in the 1900s. A three foot tall specimen, which may be 30 to 40 years in age, can be seen in the shade of a Mesquite tree in the following photograph.

These Saguaro are about to outgrow their nurse tree.

Over time, the growing Saguaro, with its extensive root system, out competes the nurse trees for water and the trees die.

The young Saguaro are very slow growing and a 1.5 inch tall specimen may be 10 years old. As they get older their growth accelerates but a 6 foot specimen will be 70 years old on average, and this is about the age when they start to flower and to develop their first arms. The arms allow for more flowering, which occurs at the top of the cactus and the tips of its arms, and more water storage. It is reported that 85 percent of the weight of a Saguaro is from water. Saguaros can grow 40 to 60 feet tall and live for 150-200 years. The tallest Saguaro ever measured was 78 feet. They can weigh up to 6 tons.

The death of a Saguaro allows one to better understand their anat omy.Inside they have wood like ribs to provide support. These can be seen in the photo below. Indigenous peoples used the Saguaro ribs for many purposes including for tools and in the construction of their shelters.

Saguaro are the keystone species for the Sonoran Desert as many organism rely on them for food and shelter. The most noticeable observation were the numerous woodpecker holes that were in the cacti. These are created by Gila Woodpeckers and Gilded Flickers who create new nesting holes for each breeding season, then other bird species take up residence in the old cavities, including Elf Owls, House Finches, Ash-throated Flycatchers, and Purple Martins.

The scenic drive was not just about the Saguaro, but also the many other species of cacti that we saw. The photo below shows several species of cacti in close proximity. In total, 28 species of cacti are found in Saguaro National Park.

Fishhook Barrel Cactus – is named for its spines that resemble a fishhook. These spines were indeed used by indigenous people for fishing as well as sewing.

Prickly Pear Cactus – here the specimens were much more robust and upright when compared to those that we have seen in the Badlands of South Dakota or the pine woodlands of the Gulf Coast.

Teddy Bear Cholla – named because the short dense needles of the cactus resembles the fur of a Teddy Bear.

Staghorn Cholla – its species name, versicolor, reflects the broad range of colors that the flowers display between April and June, including red, yellow, purple, or intermediate shades. They grow up to seven feet in height.

In addition to the cacti we saw the early wild flowers and shrubs starting to bloom, adding color to the desert. These were best appreciated by pulling over and looking around.

Brittlebush and Blue Dicks

Fairy Duster

Mesquite Bush and Lewis Flax

But the assorted cacti also provided a spectrum of color.

We especially enjoyed the yellow fruit atop of the Barrel Cacti. The fruits are edible and used in jellies and soups, or dried, and frequently sought by foragers.

The fruits of the many members of the Cholla Cacti Family also provided color. Seven species of Cholla are noted to be in the park.

Another source of color in early March were the buds and flowers of the Ocotillo, a plant frequently visited by hummingbirds. The Ocotillo were just starting to bloom.

The plant itself was interesting with its multi-stemmed arching form and its armed stems.

Perhaps the most striking photos of the first day were these captured by Ellen using a macro lens. The first is of a Cholla cactus flower,

and the second is of a flower of Santa Catalina Prairie Clover, which is also known as Indigo Bush, and is a member of the Pea Family.

Odds and Ends:

Footpaths has featured lichens on numerous occasions. They are a partnership between fungi and algae, and I would have never expected to see them prominently displayed on sun exposed rock in the demanding desert environment where temperatures can reach 113 degrees in the summer. Yet there they were, providing another color and interesting texture to the beautiful landscape.

Mistletoe was another surprise in the desert and various authorities report that 5 to 8 species of Mistletoe are native to Southern Arizona. In the southern U.S. the host plants are usually towering Walnuts, Hickorys, and Oaks, but in the Sonoran Desert nature only offers diminutive Mesquite, Palo Verde, and Ironwood trees. Frequently the biomass of the Mistletoe was greater than the host tree.

A visit to the desert would not be complete without a sighting of one Wile E. Coyote. Beep beep.

Lastly, the Saguaro take on many forms, but sometimes they may even look like someone you know. This one made us smile.

In summary, Cactus Forest Scenic Drive was a perfect introduction to the Sonoran Desert ecosystem. The vistas were outstanding and the pull outs allowed for up close study of the botany and wildlife of this parched piece of Earth. I never expected to see such color and diversity of plant life in the desert. Authorities recognize four desert ecosystems in the Southwest United States. It is the lack of freezing temperatures and the two “rainy” seasons in the Sonoran Desert that account for the plant diversity and differentiates it from the other deserts that occur in North America. The hop-in, hop-out approach to the drive gave us a more intimate visualization of the majesty of the Saguaro Cactus and a deeper appreciation for the uniqueness of the Sonoran Desert.

Footpathsblog.com posts are released every Sunday morning and some bonus content is added periodically. Please click on a social media icon above to follow for future posts and to make sure that you catch all our reflections on, and adventures with, the great outdoors.

Photo credits to Peggy Juengling Burns and Ellen Burns.

Overview:

Location – 3693 South Old Spanish Trail Tucson, AZ 85730-5601, about 20 miles from downtown Tucson.

Parking – large asphalt lot with parking for 60 cars at the Welcome Center.

Facilities – restrooms at the Welcome Center and at the picnic sites.

Trail Conditions – the trails that arise off the scenic drive are largely bare dirt and native rock/gravel.

Print Trail Map Link – https://www.friendsofsaguaro.org/vertical/sites/%7BFA6A2744-86BD-4391-A0EA-51F9464EC655%7D/uploads/Saguaro-East-Map_long_hikes1.pdf. There are also excellent park maps in the Hiking Guide pamphlet available at the Welcome Center.

Benches – none noted except at Welcome Center.

Picnic Tables – at picnic sites.

Kids – Kids four and over should do well but please understand that most plants in Saguaro are “armed” so significant oversight is needed.

Dogs – Dogs are prohibited on some trails and sites within the park. Consult the website for specifics. Where they are allowed they must be on a 6 foot leash.

Paired Hiking Trails – there a number of trails that arise off the Scenic Drive, varying in length and difficulty.

Links:

https://www.nps.gov/sagu/index.htm

https://www.nps.gov/sagu/planyourvisit/gettingaround.htm