Carnegiea gigantea
Origin: Sonoran Desert (via Peru)
Improvement status: Wild
Seeds per packet: ~8
BOTANICAL SAMPLE - NOT GERMINATION TESTED
Life cycle: Perennial
It's possible that we sometimes overuse the word "iconic" in these seed descriptions, but there's really no other way to describe the saguaro cactus. Though it's only native to a large chunk of Arizona and Mexico (with very small populations in California), it has become emblamatic of the entire southwest region, and to a large extend all deserts around the world. The saguaro is a tree-like cactus, the only member of its genus (incongruously named for robber-baron turned philanthropis Andrew Carnegie), and the northernmost columnar cactus. Some form "arms", and some never do — in fact, the tallest known saguaro was an armless individual near Cave Creek, Arizone, who toppled in a windstorm after reaching a heigh of 78 ft! — while the perhaps 1 in 50,000 saguaros that develop a fan-like fasciation are called "crested" or "cristate" saguaros (as shown in photo here).
Saguaro is a keystone species in the ecosystems it inhabits, supporting literally hundreds of other species, from birds to insects to bats to other small mammals. It also has a long history of cultural importance to Indigenous people in the region, used as food, medicine, building material, and more. The flowers, nectar, fruit and seeds are all edible. Indigenous peoples of the region (including the Akimel O'odham, Tohono O'odham, Seri, Yavapai, and Maricopa) went to great lengths to access the sweet red fruits, fashioning long harvesting sticks from dead saguaro wood to knock the fruits off the cactus, since they only grow toward the tops of the plants. The fruits were boiled into syrup and/or fermented into wine (which was often consumed ceremonially), and the seeds were ground into a meal that could be added to cornbread or other dishes. Various medicinal uses for saguaro are recorded as well, including as an anti-inflammatory, digestive aid, blood sugar regulator, and galactagogue. Only O'odham people are allowed to harvest saguaros on public land today (though visitors to Saguaro National Park may harvest small amounts for immediate consumption on site), since they're protected under the Endangered Species Act. Private land owners are allowed to harvest fruit from saguaros on their land, but they may not move or alter a saguaro without a permit. [NOTE: These seeds were harvested from a non-native population in Peru — and imported by Sheffield's Seeds in Locke, NY — which is the only reason we are legally allowed to sell them. It is legal to sell seeds from federally-listed endangered species as long as they were harvested from a cultivated planting.]
These exceptional cacti can live for over two centuries. Individual plant cells can survive over 150 years, making them the longest-living cells we know of (with the likely exception of tortoise nerve cells). The plants are very slow-growing as well. They might only grow an inch and a half in their first decade! It can take 40 to 60 years before they flower for the first time, and 70 years before they begin growing their first arm (if ever). They have a primary taproot that can reach over 3 feet in depth, and their smaller fibrous roots can extend up to 100 feet away from the vegetative part of the plant (to enable maximal absorption of water). Plants become visibly engorged following a substantial rain, and they can retain water an exceptionally long time through extended droughts. Their spines, which grow only on fresh plant growth, can reach 3 inches long and can grow 1/32nd of an inch per day. They are not barbed and are usually aseptic (free of disease-causing organisms), so they can be removed easily from human or other animal flesh, and are unlikely to cause infection unless a piece remains embedded after removal. The nectar-rich flowers open before dawn and close by the afternoon. They are pollinated by species including bees, bats, doves, orioles, and hummingbirds, among many others. Plants are self-incompatible, so require pollinationg. The fruits can be full of thousands of tiny seeds (in contrast to the most famous cactus fruit, the prickly pear — or Opuntia ficus-indica — which has relatively large seeds, with only a few dozen or couple hundred per fruit).
Saguaro are sadly becoming increasingly rare. With their limited range, hemmed in by mountains (beyond which it gets too cold for them to survive), and our dramatically changing climate, they may face extinction within the next century or so. Increasing temperatures force them to draw on water reserves at a faster rate than they used to, making them more susceptible to permanent damage or death during prolonged droughts. They are also threatened by increasingly frequent wildfires and other extreme weather events. Non-native buffelgrass from Africa and Eurasia poses a distinct risk, since it has spread widely through saguaro habitat and is a fire-adapted species with root systems that survive fires. Saguaros are not fire-adapted, since they evolved in an area where fires are only expected to occur once every 250 years or so.
Saguaro is not an easy species to grow, for all of the reasons described above, but it can survive for decades as a houseplant — and if you happen to live in a place where it can thrive outdoors, and you grow more than one, you might even be able to produce a fruit before you die (if you born in the 1970s or after)! All kidding aside, we hope many people will grow this amazing plant, both for the joy and novelty of it, and because it's so threatened in its native landscape. There may come a time when the only saguaros still alive are growing somewhere else.
GROWING TIPS: Soak seeds in water for 12 hours, then sow seed in moist peat moss, covered by just a little more peat moss. Keep moist but well-drained, and in good light (sunlight is best) and warmth (75 degrees or higher). They grow very slowly from seed and may only be 1/4 inch tall after their first two years! Hardy to Zone 8.
NOTE: The photo with the bird eating saguaro fruit comes from Quinn Dombrowski and is shared under the Creative Commons Attribution-Share Alike 2.0 Generic license. The rest are in the public domain.
