The popular name for Agave americana is typically century plant. Among the more than 200 agave species, the century plant is one of the most stunning and outstanding. Agaves come in a wide range of sizes and colors. This plant is not only drought-tolerant and gorgeous in the landscape, but it also requires little care.
Why is agave known as the “century plant”?
Agave americana L., a perennial succulent herb that may grow up to 10 m tall when in bloom, is known as the century plant. It is indigenous to Mexico and the Southern United States, and it has been introduced as an ornamental in all warm climates worldwide. Agave americana, like other agaves, has been used by Central and South American people for a long time for a wide range of things, including handicrafts, food, ethnomedicine, and cattle feeding.
Morphology
The polymorphic species Agave americana has numerous subspecies and variants, and it hybridizes with other Agave species like Agave salmania (Gentry, 1982). The plant grows from a short, thick stem that is near to the ground into a gigantic rosette with 20–40 succulent leaves. The rosette’s diameter can reach 5 meters. The leaves are stiff, nearly rigid, smooth, and 15–25 cm wide and 1-2 m long. They have a deep gutter that frequently causes them to recurve at the tip. They have huge, sharp apical thorns, straight or curved thorns, and serrated edges. With age, the teeth on the undulating, dark-brown leaf edge become grey. There are dark green forms and variegated ones with various and inconsistent color patterns, although the leaves of cultivated forms are often grey to grey-blue with horizontal stripes on the back (yellow or white stripes, pink edges etc.). A panicle resembling a candelabra that can grow up to 10 meters in length is the inflorescence. It has 15–35 branches, and the top third to half of the stalk is covered in dense clusters of green–yellow blooms. The rhizomatous Agave americana develops suckers, or base shoots, at will (Gentry, 1982; Irish, 2000; Oudhia, 2007).
Uses
The native range of Agave americana includes regions with a distinct spring season and rainfall ranging from 250 to 800 mm. Late spring and summer see high temperatures, but frosts are frequent and severe in the higher elevations of the North throughout winter (Gentry, 1982). Now that it has various kinds, they can grow in a variety of soil types and climates (Oudhia, 2007). Agave americana is a very tolerant species that thrives in hot climates with little rainfall, like southern Arizona, or in cooler settings, like the Mediterranean coastal regions, where it thrives as long as it gets some summertime water (Gentry, 1982; Irish, 2000). Agave americana grows from sea level to 2500 m height in East Africa, where it can be found in both low- and high-rainfall regions (Oudhia, 2007). The species is typically xerophytic and can endure extended droughts. It synthesizes throughout the day with closed stomata while fixing CO2 at night, minimizing water loss in leaf tissue (Oudhia, 2007; Gentry, 1982). In southern temperate areas, agave americana variants may withstand temperatures as low as -9°C and possibly even lower (Gentry, 1982; Irish, 2000). The agave americana can withstand wind, salt, hot weather, and severe drought. It may colonize bare sand and grow in shallow, extremely dry, poor fertility soil. It has a wide range of soil type tolerance (GISD, 2020; Gentry, 1982).
Because it is a monocarpic species, the agave americana perishes after fruiting. The “century plant” only blooms once, after roughly 10 years in warm climates or up to 35 years or more in cool climates (GISD, 2020; Irish, 2000). The plant blooms in its natural habitat from June to August (Irish, 2000).
Establishment
Agave americana can grow by a number of means. It can procreate by dispersing seeds, which have a high rate of germination (GISD, 2020). However, plant and stolon (suckers) pieces are the typical technique (GISD, 2020). It is established via suckers or seedlings that are two years old. The furrows are spaced 3 to 5 m apart, with the plants being planted 1 to 2 m apart. It is advised that you plant it beside or next to fences (De Kock, 1980). Rhizomes are another way the plant can reproduce. The flower stalks yield bulbils, which can also create daughter plants (GISD, 2020).
Invasive plant
Many nations in southern Africa, particularly South Africa, view Agave americana as a noxious invasive weed (Oudhia, 2007). Due to its invasive nature, this plant shades out native species and depletes their resources with its extensive network of rhizome offshoots. Rhizomatous plants have the potential to change the soil’s nutritional composition. It is more challenging to control feral animals in South Australia because of the presence of exotic animal species there, such rabbits. Combining physical removal and herbicide treatment is used to control (GISD, 2020).
Oxalates
The leaves of the agave americana contain calcium oxalate crystals that resemble needles and are known as raphides; they can lead to conjunctivitis and contact dermatitis (Oudhia, 2007). Oxalates bond with calcium ions when consumed, rendering calcium inaccessible to the animal. (Hobson, 2016) Three scenarios have been described.
- Agave americana can cause hypocalcaemia in unadapted animals, which can lead to weakness, paralysis, and eventually death. Renal failure is brought on by Ca-oxalate crystals blocking and harming kidney tubuli.
- Oxalates are ingested in excess by animals with adaptations, and not all of them are detoxified in the rumen. Bone abnormalities, poor milk supply, slow growth, kidney and bladder stones, and gastrointestinal stasis are all effects of calcium insufficiency.
- A meal high in leaves may create acidosis due to the total sugar content and quick digestion of the fiber, which can lead to lameness similar to diets high in grains.
Therefore, it is advised to limit intake, avoid using it as the only feed, avoid rapid exposure to the plant, and complement the diet with calcium-rich foods (dicalcium phosphate as a lick or mixed in the supplementary feed, addition of lime).
Utilization
Agave americana leaves alone cannot be a maintenance ration due to their low protein content and high water content. To avoid the harmful effects of oxalates, which can occur if they are fed alone and consistently, they must be supplemented with enough alfalfa hay and other feeds. As the succulent component of the ration, agave americana leaves can, to a significant part, replace silage, fodder beets, etc (De Kock, 1980). According to a South African study, agave americana leaves may meet 64% of the maintenance needs of senior sheep, but the best results come from using only 45% of them in diets that also contain 55% alfalfa (Hobson, 2016).
Ostriches
Agave americana was studied in South Africa as a nutritional supplement for ostriches. The TME value of the daily removed from the main plant and chopped into small blocks of agave leaves was 12.2 MJ/kg DM, or roughly 80% of maize’s value. In more extended feeding circumstances, it was proposed that Agave americana might be utilized as a feed supplement for maize in birds older than six months (Cilliers, 1998).
Agave blue is a century plant, right?
My half-acre garden’s largest succulent ever was an Agave americana that we called “Large Blue. It appeared capable of eating visitors who took selfies with it because of its six-foot leaves, which were laced with razor teeth. Agave americana is frequently known as “Big Blue’s lifespan was only 20 years, despite the fact that it appears to take an eternity for it to flower and die.
I didn’t always get along with Big Blue. It occasionally snagged my skin and drew blood, and it was armed and dangerous. Usually, I was to blame for this. I like getting close to it to snap pictures of the bud impressions and scalloped lines left by the pressed-together leaves before they spread out.
Additionally, it attempted to monopolize the garden by growing pups (clones) from its roots. These suddenly appeared in all directions, even uphill. My neighbors’ decision to put it out in the trash in the first place was presumably because to century plants’ propensity to spread like strays dogs. However, when I saw the 2-foot pup, I knew it would look excellent in a pot because of the way the terra-cotta orange of its leaves contrasted with it.
That was seven years ago, and I still had a lot to learn about agaves before my first book about succulents was published. The pup had been severed at ground level, so I didn’t believe it would survive. However, after a few months, it grew and flourished. I left it in the pot where it stayed little and planted it in the garden a few years later.
As other ornamentals came and went, Big Blue became bigger and bigger. In 2007, a Bailey’s acacia that was planted close by grew to be a 20-foot tree. I used to marvel at how the agave’s gutted leaves directed water to the roots every spring as I washed away acacia blooms that had fallen to the plant’s center.
Although it doesn’t require it, agave americana enjoys watering, so early on I capped neighboring risers. Peevishly, Big Blue damaged a pipe that could not be fixed since it was hidden beneath thorny leaves. (I should have anticipated that.) I cut off the line and then spent countless summer afternoons watering with a hose.
Friend who is a landscape architect said, “Debra, you are aware that the route will eventually be overgrown with Americana. It was only five feet away, so that seemed implausible. I answered, “I’ll merely move the pathway after that. And I did so six years later.
When digging up puppies, we wore safety glasses. I gave everyone who would take my tiny century plants. However, because they arrived with warnings, the majority remained in 1-gallon nursery pots without adoption. During the winter rains, the leaves first shrank and then grew. Some of the naughty little ones poked their roots through the perforations in their pots.
I produced a YouTube video with Big Blue: “You MUST know these things about Century Plants. There I explain “the pupping issue and the oversight of not estimating the size of an agave before planting it.
Big Blue finally reached the sugar content required for flowering in February 2018, which was a major accomplishment that resulted in an abundance of flowers followed by seed pods. Pollinators buzzed around the 30-foot bloom spike of the agave that summer.
Big Blue’s sailboat-mast spike was tilting at a 45-degree angle toward the street, so keeping what was left of it wasn’t an option. That October, I recorded the removal of the agave.
A few years ago, when I was aware that Big Blue would eventually die, I made the decision to maintain a favorable offset. Its current size is only about one-fourth of what it will eventually be. Although Big Blue Two has started puking, I am still happy to have it even if I don’t get romantic over succulents (sigh).
Spring 2019: All that’s left of Big Blue is a stump. Left is its clonal equivalent.