Trees growing in the rock walls of Zion National Park
I remember being in college the first time I heard of the Hanging Gardens of Babylon, considered by many to be one of the seven wonders of the ancient world. I pictured these mythic gardens as masterpieces of flowers and greenery that were somehow suspended dozens of feet in mid-air. According to ancient texts, though, the gardens weren’t hanging in the literal sense, but only appeared to be floating: this was due to a remarkable product of human ingenuity.
The story goes that King Nebuchadnessar II built the gardens for his homesick wife who found the flat, desert terrain of Mesopotamia depressing. To please her, he created an artificial mountain out of red clay bricks and embellished it with a series of tiered gardens. The plants, which included trees, shrubs and vines, cascaded from the many terraces, giving the impression that they were floating.
Artist’s rendering of the Hanging Gardens of Babylon/Photo: unmuseum.org.
By some accounts, the gardens measured 400 feet wide by 400 feet long and towered as high as 80 feet in the air. A stairway led to the uppermost level. Beside the stairway were a series of mechanical screws through which water was pumped from the Euphrates to the top of the garden. Once the water reached the top, it then trickled down to feed every plant on the terraces. Historians estimate the gardens may have used up to 8,200 gallons of water a day to irrigate the plants in this fashion.
Whether or not the Hanging Gardens of Babylon every existed, I later learned that hanging gardens do flourish in many parts of the world, and just as in Babylon, they often take root in desert environments. Unlike King Nebuchadnessar’s garden masterpiece, however, they are naturally generated and need no help from man. But don’t discount them; they are every bit as grand a feat of landscape engineering.
About Hanging Gardens
Of the many beautiful hanging gardens to be found around the world, Zion National Park lays claim to some of the most unusual. This is largely due to the rock formations that make up the park. These formations, known in geology as the Navajo Formation, provide the perfect environment for hanging gardens to develop.
Unlike their more pampered cousins, Zion’s hanging gardens are composed of plant communities with a singular ability: they are able to establish themselves in rock, often in desert environments that are hostile to their very survival.
How do they do this? The deep red sedimentary rock, while by all appearances solid, is highly porous. This allows it to soak up rainwater like a sponge, creating a unique habitat for water-loving plants to thrive in places they would normally never be able to grow.
The combination of porous sandstone and adjacent levels of impervious (Kaibab) limestone, create the perfect conditions for hanging gardens of all kinds to establish. As water seeps down through the sandstone, it pools in places where it encounters the impenetrable stone. Then, as gravity does its magic, the water fishes its way downward through joints and cracks in the impervious strata, slowly nourishing the plants that cling to its rocky walls.
Water ‘seeps’ can range from small moist patches on stone, to short-lived trickles, to full-fledged gushing streams or pools that weep all year. A true hanging garden forms where there is constant seep as well as shade during much of the day to keep plants lush and moist. Plants like ferns, wildflowers, grasses and mosses are often found in these well-watered areas.
It’s a lot like a vertical garden.
The Phenomenon of Weeping Rock
Zion’s most famous hanging garden is called Weeping Rock. It is reached by a short but steep trail up a rocky hillside. As the path clears the final rise, dry sand and gravel give way to moss and slippery rocks fed by long ribbons of water oozing from a canyon above. Formed of impermeable shale, the canyon floor sheds the water down through the porous rock until it finally finds a place where it can penetrate.
At Weeping Rock, the permeable layer has eroded further than the impermeable layer of rock, forming a shelf where water can collect. The water streams down the sandstone walls and across the terrace, eventually cascading over the edge into a pool below.
Weeping Rock at Zion National Park
Pool where water collects under Weeping Rock
Weeping Rock is best viewed from beneath its natural arch, which features a garland of mosses and ferns. The seeping walls of the crescent-shaped stone terrace are home to lush green vegetation, which includes wildflowers, ferns, grasses and orchids, all of which can be found growing straight out of the rock. Some are even growing upside down.
The columbine Aquilegia grahamii, known to grow in extremely fragile environments, is one of many exotic plants found growing in the sandstone. Its brilliant yellow and mango blooms add a colorful touch to the red stone walls.
Aquilegia grahamii columbine
Other beautiful flowers found growing at Weeping Rock include orchids and monkey flowers, to name just a few.
Orchid and columbine growing out of the rock walls of Zion
For more information on Zion National Park and its hanging gardens, click here for the National Park Service website.