The Illustrious Agave Bloom
Our Agave parryi ssp. neomexicana, formerly known as Agave neomexicana, first showed signs of sending up a stalk in preparation for reproduction – or flowering – on April 24th, 2019. I was given a beautiful 5-gallon sized plant about six or seven years ago, so it’s difficult to pinpoint exactly its age. My best guess is it's around 15 years old, within the typical 8-20 year bloom range. Agave’s only bloom once, they’re monocarpic, so it was with great anticipation I watched its progress.
I have seen agaves in bloom before, on spring vacations to the desert southwest, and in our own botanic garden in Amarillo. In visiting botanic gardens in Texas, Arizona and California, I was able to see several different agaves species in bloom. Because of their size and their singular bloom cycle, viewing them in bloom is an occasion. Three species have bloomed at the Amarillo Botanical Gardens in the past recent years: Agave harvardiana, Agave parryi ssp. neomexicana – both cold hardy – and A. desmettiana, which is not cold hardy for the Texas Panhandle.
I can only imagine the awe many of the first explorers to the New World felt upon seeing agaves in bloom – a plant unlike any they had seen growing before. The first mention was by Columbus, where he referred to it as an aloe, an evergreen succulent native to Africa. The first Spanish Conquistadors are credited with their introduction to Spain and dispersed in Europe around 1521. Within a few decades, agaves, most likely Agave americana, were growing in many of the most important gardens of Europe where it was called Maguey, its New World name.
The first mention of an agave flowering in Europe was in 1561 in Florence, Italy. The thrill of discovery these botanists experienced must have been incredible as they watched it day by day, wondering what would transpire. While our Mescal or New Mexican agave sent up a stalk 15 feet high with 20 short candelabra-like branches, the Agave americana itself can grow to a size of 10 feet tall by 13 feet wide, and its panicle inflorescence will rise from 16-26 feet tall with 15-35 branches. Doubtless, there was more than one viewing party as the spectacle progressed. Drawings and descriptions were made and sent around to fellow botanists throughout the learned world.
Linnaeus described the genus in 1753, calling the plants Agave, from the Greek ‘agavos” meaning “illustrious” or “noble”. Agave americana is the species of the genus Linnaeus used as the type plant to describe the genus, a magnificent and noble species indeed. We call agaves "century plants" due to the length of time it requires to mature and bloom.
It took until 1774 for the first recorded blooming of an agave (at 28 years of age) in England – that bastion of horticulture excellence. In cooler climates, agaves may take many more years than the 8-20 average to bloom. Agaves in containers and conservatories may never bloom, or take a really long time. One speciman in a Michigan botanic garden took 80 years before blooming. It’s 27 foot stalk grew so tall, they had to remove glass panes to allow it to complete its growth and bloom.
By the eighteenth century, agaves were a common sight around the Mediterranean and southern Europe. Agaves could be found in conservatories from Germany to St. Petersburg by the mid to late nineteenth century. Victorians considered them an exotic novelty, as greenhouses were generally necessary to winter them over. Italian and Mediterranean gardens used them extensively in containers and in-ground focal points, climate permitting, much as they do today.
New Mexican or Mescal Agave Description
Notwithstanding the flowering of an agave, the plant itself is fascinating. Jill Nokes, states in her book How to Grow Native Plants of Texas and the Southwest that: “It is no exaggeration to state that whole cultures depended on the Agave. Agaves have been used in a multitude of ways – as food (for both humans and livestock), as nutritional and alcoholic beverages, and as a source of fiber for weaving mats, making clothing, fashioning tools and utensils and building shelter.”
Seeds of agaves are viable up to five years, with germination within one to three weeks, depending on soil temperature. Seedlings are succulent and look like true leaves. The seedlings develop their rosette form along with a minute terminal spine very early on. The rosette is an adaption common to arid or desert environments, which allows water to be funneled down the leaves to the root zone. Shade the very young plants from full sun during the summer to prevent sun scald. New Mexican agave leaves are a light glaucous blue or grey-green color, hard, and stiff and fibrous inside. Most agaves, including New Mexican agave, have sharp teeth along the margin of the leaf and a very sharp terminal spine, about an inch and a quarter long. This can be a dangerous plant to garden around!
Agave leaves are evergreen, thick and succulent for water storage, and are coated with a waxy cuticle that prevents evaporation; they are glabrous (without hairs). Their leaves are long lived, and can even live the life of the plant. However, if they are damaged by injury, animals or hail, leaves of the bottom rosette die and are gradually replaced from the top down. If the plant remains undamaged, new leaves can be held in bud stage 2-3 years, and in some species, including the New Mexican agave, the teeth leave an imprint in the surrounding leaves, which is referred to as the bud imprint. Arid regions aren't favored with delightful evergreens such as boxwood for the landscape, but they do have equally, though quite different, evergreens, such as agaves, yuccas, cacti, etc. for use in the landscape that I call southwest evergreens. (For more plants I call southwest evergreens, check out the categories in my Plant List.)
No one has determined exactly what the bloom trigger is. However, after the plant has stored sufficient nutrients, usually 8 – 20 years, it sends up a tall asparagus-like stem or stalk with candelabra-like branches. The inflorescence is a panicle with branching beginning about midway up the stem. Its tubular flowers are red in bud and yellow when open, normally blooming in June or July.
Why such a long stem? The main pollinators of agaves throughout its range are bats and hummingbirds. Perhaps growing a long stem with such showy flowers was meant as a signal flag waving in the breeze to their pollinators. Up off the ground such a height kept ground level animals from consuming the rich and abundant nectar. As the tip emerges, it would be tender and tasty to eat, like an asparagus tip. The young tip was roasted and eaten by indigenous people and is said to have a taste like molasses. If the tip wasn't taken, the flowers were boiled or roasted. (Eat the Weeds website has some information on edible uses.) Some agave flowers are fragrant, however, on our agave, the flowers were too high up for me to notice.
Agaves reproduce by offsets (pups), seed and rarely, bulbils. Agaves grown in cultivation will look slightly different from those growing in native conditions. Agaves hybridize easily with others in its genera; cross pollination in likely when plants are in hummingbird range of other agave species, which also accounts for variation in their appearance.
This New Mexican agave isn’t the first or only agave I have in my garden, but it was the oldest. I’ve long wanted one of them to bloom; each spring would find me watching closely for signs of stem emergence. Scientists have yet to determine exactly what combination of factors triggers the bloom cycle, but they do know the plant must have stored sufficient nutrients to support their massive stem and flowers.
It was with great delight and excitement I first noticed what appeared to be the first tip of the stem. Having watched agave blooms on a weekly basis at our botanic garden, I was elated to be able to watch it hourly, if I choose, but certainly, daily. I took photos of this marvelous plant nearly every day for the first 6 weeks, then several times a week until the it finished blooming. Each morning, I made sure to check its progress. Afterwards, I photographed it less frequently until the end, but watched it daily. From stem to first emergence to the end of flowering was a period of 10 weeks.
Brief viewers guide to Agave parryi ssp. neomexicana’s bloom progress:
April 25th – First emergence of the flower stalk. At this stage, the stem is edible when cooked, but then, the flowering will be damaged, depending how much stem is taken. Removing the stem will not prevent the agave from dying.
May 2, One week later – Stalk is about 12-15 inches tall.
May 9th, Two weeks later – Stalk is about 6 feet tall. Its resemblance to asparagus is striking. It’s in the Asparagales family, Agavoideae subfamily.
May 13 – Top of stalk bends slightly west. I think perhaps the flowers are positioning themselves to separate from the stem.
May 19th – Stalk straightens up again.
May 15 – After only three weeks, first sign of flower buds appear, stalk is approximately 10-12 feet tall. This growth stage was astounding!
May 16th – The next day, first branch, or arms begin to separate from the stem.
May 24 – Thirty days after stalk emerged, all branches have separated from the stem.
June 12 – 49 days after stem emergence (seven weeks), first flowers open, starting at the panicle (loosely branched flower cluster) of the lowest branch – it blooms from the bottom up.
June 16th – Flowers are opening on up on branches midway up the stem, bees and ants are noticeable, seeking the nectar that fills the yellow tubular flowers on the lower branches. Although I watched closely every day (but not at night), I did not see a hummingbird or bat pollinate the agave.
June 19th – Flowers open two thirds of the distance up the stalk, bees are noticed moving further up the panicles as the flowers mature.
June 22 – Flowers open three fourths of the distance up the stalk.
June 25th – Flowers have opened up to the very top panicle.
Beginning of July –Succulent leaves of agave begin to brown. Browning begins at the stem, and moves outwards, on the bottom leaves first on up the spiral rosette. The browning indicates the agave makes a final push in sending all its stored energy from the leaves into seed production.
August – The stem tilts slightly as the agave continues to loose viability, devoting its energy to seed production.
Mid-August – Leaves of the agave are completely browned out and dead, although the stem is still green and full of fluid.
September-October – The stem turns brown, having lost most of its fluid. Tubular flowers form fruits that are actually woody capsules that remain on the plant for months. Each capsule, of which there are hundreds, contain a hundred plus black, flat seeds. Bees must have pollinated the flowers. The capsules eventually split open (dehisce) and seeds drop to the ground, especially over time, when the stalk tips over.
First week of November – I removed the paper dry, lightweight leaves, once so thick and succulent, starting at the bottom. If one removes them in sequence at the bottom, tearing them away from the stem in the spiral pattern they have grown, they come away very easily, being very careful of the strong, sharp teeth that line the margins. This agave was a healthy, robust specimen with about 12 - 15 layers of leaves. The teeth have lost none of their bite through the agave’s magnificent death spiral. The stalk was easy to saw off. After digging out the roots, one of the larger pups, or offsets, growing nearby was planted in its place, ready to start the cycle again. The entire agave stem is quite lightweight at this point.
November 15th – Strung lights on agave for holiday ornament and set stalk in ground near our house. These dried flower stems are often used and prized in southwest gardens as accent pieces.
Agaves are a plant genus that are entirely native to the New World, the Americas, including the West Indies. The genus consists of approximately 211 different cataloged species and subspecies and a growing number of varieties and cultivars (with new species currently being discovered). Agave species grow in mostly arid conditions in poor soils, natively from sea level to more than 7000 feet in elevation in forests, dry hillsides, arid plains, deserts and on the seashore. Approximately 75% of agaves are native to Mexico and only fifteen species native to the United States. Nine species are native to Texas (Nokes).
The New Mexican agave is native to Texas in a limited region just south of the New Mexico border on rocky limestone slopes and grasslands. It can also be found in the adjacent mountains of New Mexico. For many years it was classified as its own species, but was reclassified within the past two decades. My plant grew to at least 2 feet wide by 2 feet high or more -- a little bigger than normal. This could be because of increased moisture in the Texas Panhandle versus the more arid desert.
Agave parryii ssp. neomexicana is an awesome agave for the garden, either in a container, or in-ground. Cold hardiness is reported to be somewhere between zero and -20°F, depending on the reference. My New Mexican agave has survived winters down to -8°F on a northern exposure, in full sun. These agaves tolerate full summer sun and have extremely few problems (I’ve had no problems). New Mexican agaves can survive with normal rainfall very well in the Texas Panhandle; in periods of extreme drought, supplement with an inch per month during the summer. Planting in good draining soil is advisable for a long healthy life in which this plant will provide, not just a stunning evergreen presence in the landscape, but a magnificent blooming plant that will delight you and your neighbors for weeks. Try one, and with patience, you won’t be disappointed!
Desert-Tropicals.com, article on Agaves: http://www.desert-tropicals.com/Articles/Agave/
Irish, Mary and Gary, Agaves, Yuccas and Related Plants A Gardener’s Guide, Timber Press, 2000.
Lady Bird Johnson Wildflower Center Plant Database, Agave parryi ssp. Neomexicana.
Nokes, Jill, How to Grow Native Plants of Texas and the Southwest, revised edition, University of Texas Press, 2001.
Angie Hanna, November 21, 2019