December 2018 Plant Profile: Agave parryi

Agave parryi var. truncata, photo by flickr user Tony Rodd

This plant came to my full attention when it recently flowered. Of course I had to find out more and started research which turned up stories on historical plant collections, tequila production, semelparity in reproduction, and the ethnobotany of the agave. I also established a ‘flower watch’ regimen in June and started featuring the plant on many public tours.

Its genus name, Agave, is from the Greek word agauos, which means noble or admirable. The species is named in honor of Charles C. Parry (1823-1890), a member of the US and Mexico border survey between 1848-1855, who worked as a surgeon and botanist. In the latter profession, he identified and named many plants native to the area – including the Torrey pine and Englemann spruce.

Original Arboretum accession records are murky, but according to Ray Larson, Curator of Living Collections, “the ledger .. offers more clarity as to the plant’s origins. It looks like this was received as many divisions (“ca. 25”) from a plant that longtime Arboretum Foundation volunteer, (and especially prolific photographer) Joy Spurr, had growing in her Seattle garden. She had collected seed from the agave in the Kofa Mountains south of Quartzite, Arizona, and these were divisions from the resulting plant. The agaves in the Graham Visitors Center parking lot were first noted in 1999 but no planting record was found.”

So we can’t know what year it was actually planted between 1987 and 1999; it could have lived in a container for some time before being installed in the rockery above the parking lot. Over the years a neighboring Ceanothus shrub has grown to shade over the agaves underneath. Roy Farrow, UW Botanic Gardens’ horticulture supervisor, has kept the shrub pruned back so the agaves underneath receive as much light as possible, but other than that he says the plants were pretty maintenance free.

I have long admired its attractive blue-gray evergreen leaves (to 12” long with spiny margins and a 1” terminal spine) which form a symmetrical basal rosette – as the leaves unfurl from the center, the impression of the leaf unfurling is left on each leaf underneath. This impression adds an attractive texture to each leaf.

Agave can reproduce vegetatively by suckers/offsets which root at the base of the rosette forming over time a colony of rosettes – just as we see in hens and chicks sedums. It can also reproduce by seed, but only once and then the plant dies. This is called semelparity. Semelparity in plant reproduction is not unusual. Bamboo, hens and chicks sedums, and most grasses are semelparous. Many animals also reproduce through semelparity including octopi and salmon.

The agaves usually flower between 10-15 years old but sometimes flowering will not occur until 20-30 years of age. At the ripe old age of 31-32 our Agave parryi went to bloom this last spring! The stalk was about 15’ tall and shot up through the neighboring Ceanothus shrub, towering 6’ above the shrub top. Before the flowers unfurled, it looked just like a giant asparagus stalk. This was the point at which my attention was piqued, I began researching agave reproduction, and following the plant’s progress on a weekly basis.

Pictures of agave stalk in development, 5/29 and 6/19
Left: May 29, 2019. Note the pinkish bud tip of the agave stalk poking through the top of the flowering Ceanothus shrub. Right: June 19, 2019. Flower stalk fully extended, buds have not yet opened.

In its native habitats Agave parryi will send up one huge 20’ tall flowering stalk in summer season – each stalk will produce 20 to 30 side branches containing a large cluster of creamy yellow flowers. According to US Forest Service blogger, Charlie McDonald, “You have to be impressed when you see a stand of flowering Parry’s agaves for the first time. Each flowering plant has a giant stalk up to 20 feet tall with 20 to 30 side branches and each side branch with hundreds of flowers. The flowers are reddish in bud and bright yellow when open. Just magnificent!”

As I watched the progress of the flowering and began to learn about semelparity, I became slightly obsessed with and proud of our agave. It bloomed in late June/early July, and as the gorgeous flowers broke bud and spread their orangey-yellow petals, it was truly spectacular.

Agave parryi flower stalk on July 11, 2018. After it had fallen over due to the weight of the flowers.

One Sunday in July I went to visit the agave and found to my dismay the flower stalk fallen over, bent about 4’ up the stem. The top of the stalk was almost touching the ground below the retaining wall with the flowers were facing downward. I was certain that was the end. Roy decided to leave the stalk as it was rather than attempt to stake it up and possible break it. When I returned next Sunday – the flowers had completely turned 180 degrees, were facing up to the sun and continued to mature afterwards.

After the flowers were done, the seed pods began to engorge and the leaves of the basal rosette turned brown and began to wither.

According to Robert E. Ricklefs “Physiological studies have shown that the growth of the flower stalk is too rapid to be fully supported by photosynthesis or uptake of water by the roots. As a consequence, the nutrients and water necessary for stalk growth are drawn from the leaves, which die soon after the seeds are produced.”

My research on the agave shows the flowers are usually night-pollinated by bats and moths, but they can self-pollinate as well. Since there was not another flowering agave near by it was questionable if the seed would be viable. A germination experiment by a volunteer guide using seed collected from a pod fallen to the ground achieved successful germination.

Agave parryi seeds after germination.

One could conclude that the flowers self pollinated, but I am not an expert nor a botanist so can make no final definitive statement about this. The rest of the seed pods were harvested from the plant last week and their future use has not been decided yet.

These agaves have an interesting ethnobotanical history as well.  Archaeology has shown that going back at least 9,000 years agaves have been a source of human food, medicine, fiber for baskets and clothing, and a beverage.

According to McDonald, if the leaves are trimmed away just before the plant flowers, the stem can be cooked to be edible. “Native Americans of many Southwestern tribes pit-roasted agaves in an elaborate process that took three or four days of cooking. The sweet meat is said to have a flavor of sweet potato, molasses, and pineapple, but is quite fibrous. Chunks of roasted agave were chewed and the tough fibers discarded. Roasted agave could also be pounded into cakes and dried for later use.”

Of course, the most famous use of Agave parryi is the liquor mezcal. This process takes several steps beginning when the agave’s central bud is removed. This leaves a cavity, which fills with nutritious fluid called aguamiel (translation = honey water). When the aguamiel is allowed to ferment it becomes an alcoholic beverage called pulque, and when pulque is distilled it becomes mezcal (which technically can be distilled anywhere). Tequila is a high quality mezcal produced only from Agave tequilana grown in limited regions of Mexico.

Botanic Name: Agave parryi var. couesii
Common Name: Parry’s Agave, Mescal Agave
Accession Number: 1-87
Location: NE corner of parking lot at the Graham Visitors Center in the Washington Park Arboretum
Family: Asparagaceae
Range: Arizona, New Mexico, Mexico
Size:  1-2’ tall by 2’-3’ wide.  Flower stalks can be 20’ tall.
Habitat: desert land: chaparral, desert scrub, pinyon-juniper and oak woodlands typically at elevations from 4,000 to 8,000 feet
Historical use: alcohol production of pulque and mezcal. Native Americans used this agave species as a source of food, fiber, soap and medicine.

References:

Cacti, Agaves and Yuccas of California and Nevada, 2008, Ingram.
Growing Succulent Plants, 1987, Graham.
The Economy of Nature: Data Analysis Update, 2007, 5th edition, pp 212-13, Ricklefs.
http://www.missouribotanicalgarden.org/PlantFinder/plantFinderDetails.aspx?kempercode=e965
Charlie McDonald,  https://www.fs.fed.us/wildflowers/plant-of-the-week/agave_parryi.shtml
https://en.wikipedia.org/wiki/Charles_Christopher_Parry
https://www.theglobeandmail.com/life/food-and-wine/wine/whats-the-difference-between-mezcal-and-tequila/article35004748/

2 Responses to “December 2018 Plant Profile: Agave parryi”

  1. Nancy Simsons

    Thx for the in depth article about the Agave. I’ve seen it many times with you during the tours. I had an Agave parryi in a container in a container. Rather than put it in my clay soil where it would most likely die, I gave it to a friend who was thrilled!

  2. That was interesting. I have been watching these Agaves for years, but had not been to the Arboretum yet this year to notice one had flowered. That is exciting to see, and that it has produced seed.

    I should note that Agave parryi has not been recorded from the Kofa Mts and is unlikely to be native there. A. deserti subsp simplex is the only Agave recorded from that area. I wonder if this may have something to do with the label on them saying A. deserti. However, based on limited experince with that species in the Northwest, it would be very unlikely to survive even one winter outdoors here. The appearance of the plants and the fact that they have survived all these years point to A. parryi being the correct ID. But, I don’t believe they can be from the Kofa Mts.

    Numerous creatures find Agave flowers attractive enough to visit (i.e. pollinate) well out of their native range, including bees, moths and hummingbirds. This is noted in Gentry’s Agave monograph.