Visiting Agave utahensis var. nevadensis in habitat

My Las Vegas trip in early April was full of amazing sights, but my personal highlight was seeing Agave utahensis in its native range. We visited the habitats of var. nevadensis and var. eborispina, the two most sought after varieties, and seeing them growing in what most other people would consider inhospitable wasteland was a bucket list experience. Often they seem to grow right out of the limestone, with nothing but a small pocket of soil holding the roots in place. And yet, these are tough plants, thriving in temperatures that range from far below freezing in the winter to way past 100°F in the summer. All I can say is that if I were an agave, I would not be an Agave utahensis; I prefer a decidedly more moderate climate.

The drive from Las Vegas to the habitats we visited took us through beautiful scenery. In the photo below, the flat areas are dominated by Yucca schidigera, the Mojave yucca:

The map below shows in broad strokes where the various subspecies and varieties of Agave utahensis are found. I'll share more details on the taxonomy at the end of this post.

Since both var. nevadensis and var. eborispina are heavily poached, exact habitat locations are kept secret. These agaves are under constant human threat, yet they are not considered endangered on a federal level. On the state level, var. nevadensis is rated S2 (Imperiled) in California and S3 (Vulnerable) in Nevada; var. eborispina is rated S3 (Vulnerable) in both states. In practical terms, these ratings don't mean much because they don't confer any real protection. No matter how much we may condemn removing these agaves from the wild on environmental and ethical grounds, it's technically not a crime from what I was able to determine. What we need is legislation similar to the Dudleya protection law California passed in September 2021 (AB 223) which would have real teeth.

This post is about Agave utahensis var. nevadensis. Here is a separate post on var. eborispina, arguably the most spectacular form of Agave utahensis.

As I mentioned earlier, Agave utahensis var. nevadensis grows in ostensibly bleak and barren environments at elevations between 3,000 and 6,000 ft. Below is a great example. Start by looking for the flower stalks; those plants are the easiest to spot. (Or simply look for Justin crouching down in front of one.)

We also saw a few plants that we just starting to flower on new flower stalks:

Here's Justin taking a photo of a nice clump of var. nevadensis:

Both var. nevadensis and eborispina often grown right next to cotton-top cactus (Homalocephala polycephala, formerly Echinocactus polycephalus):

Here's a nevadensis next to a spiny star cactus (Escobaria vivipara var. deserti):

Agave utahensis var. nevadensis generally doesn't have the impressive terminal spines of var. eborispina, but it's highly decorative plant in its own right:

Some individuals do have spectacular terminal spines – long and twisted just like var. eborispina:

Taxonomy of Agave utahensis

In Agaves of Continental North America (1982), the father of agave taxonomy, Howard Gentry, divided Agave utahensis into two subspecies (ssp. utahensis and ssp. kaibabensis) and two varieties (var. nevadensis and var. eborispina). For the sake of consistency, that's the convention I'm following in my posts.

However, the Agave utahensis complex is quite variable, and even in a single population there often is a range of different forms. That's why the most recent classification by German botanist Joachim Thiede in Illustrated Handbook of Succulent Plants: Monocotyledons (2001) recognizes only two taxa: ssp. utahensis and ssp. kaibabensis. Var. nevadensis and eborispina are subsumed into ssp. utahensis.

There's a great deal of discussion, often heated, between these two camps. As much as I appreciate the sense of order taxonomy brings, I try to focus more on what really matters to me: the beauty of these plants, no matter what their current taxonomic ranking might be.

Cultivation of Agave utahensis

Like many other agaves from extreme climates, Agave utahensis can be challenging in cultivation. The key is to plant in extremely well-draining soil, ideally on a mound, and to mimic the natural rainfall patterns of its native habitat: keep dry in the winter and water regularly in the summer. 

I live in a winter rainfall climate and have lost several plants to rot. Right now, all my nevadensis and eborispina are in pots, but I plan to put some in the ground on small mounds tightly confined by rocks to restrict the amount of soil available to the roots.

There are plenty of seed-grown plants available so please don't buy a poached plant through eBay or a similar source. If a plant looks fairly rough and has few or no roots, assume it was removed from habitat.

Differences between var. nevadensis and var. eborispina

As I mentioned earlier, some taxonomists now think nevadensis and eborispina are simply local variations of Agave utahensis ssp. utahensis. In general, var. eborispina has much longer cream-colored terminal spines, often twisted into corkscrew shapes, but we saw var. nevadensis with long terminal spines as well. Some sources say var. nevadensis has bluish leaves while var. eborispina is more green than blue. Another difference I've heard is that var. nevadensis offsets, often prodigiously, while var. eborispina is generally solitary, although we did see clumps of eborispina in habitat. It's impossible comparing the two varieties side by side because they grow in disjunct populations, never together. 

Suggested reading

The wonderful Czech online journal Kaktusy has a special edition dedicated entirely to Agave utahensis: “The Agave utahensis Complex” (Kaktusy 2010 Special 2). You can read or download the English edition for free from this link. The author, Zlatko Janeba, has traveled widely throughout the range of Agave utahensis and shares beautiful photos from his travels.

Cultivation information

Daniel Zarrella (Mojave.lv) has dedicated himself to preserving Agave utahensis in habitat. His Project Eborispina is the first endeavor of its kind to produce statistically defensible estimations as well as a visual record of Agave utahensis var. eborispina populations in Southern Nevada. His YouTube channel contains a wealth of information, including in-depth Agave utahensis cultivation videos covering things like soil mix, watering, and fertilization. To finance his research, he sells seed-grown Agave utahensis plants through his website. Check out what he's doing on YouTube and Instagram.

RELATED POSTS:

• Visiting Agave utahensis var. eborispina in habitat
• April 2022 Las Vegas trip — list of posts

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