Visiting Agave utahensis var. eborispina in habitat

As I mentioned in my post about Agave utahensis var. nevadensis, seeing the two varieties of Agave utahensis native to western Nevada—var. nevadensis and var. eborispina—in habitat was a bucket list experience. It's one thing coming across cool plants in a botanical garden or a private collection, but something else entirely being able to study them where they grow naturally. 

In the case of Agave utahensis var. eborispina, that environment is harsh in every conceivable sense of the word. It's amazing to see how well these plants have adapted. They thrive in extreme temperatures from below 0°F in the winter to above 110°F in the summer, and they make do with very little soil, sometimes appearing to grow right out of solid limestone.

Agave utahensis var. eborispina

Agave utahensis var. eborispina differs from var. nevadensis in leaf color (olive green vs. blue green) and length of spines: The terminal spines of var. eborispina are noticeably longer, sometimes twisted into fantastic corkscrews. Side-by-side comparison aren't possible because the range of the two varieties doesn't overlap.

In the locality Justin and I visited, there were so many eborispina (fortunately!) and I took so many photos that it was difficult to pick the ones that are most representative of what we saw. Depending on how much soil the plants have, they range from tiny to a foot across. Some specimens were spectacular, others looked like they were struggling to make a go of it. 

There were many flower stalks from previous years, their seeds scattered, as well as plants just starting to flower. I can't assess the health of these populations, but considering the ongoing threat from poaching, it was heartening to see so many plants, including young ones.

Perfect rosettes above, squished into a pancake below:

California barrel cactus (Ferocactus cylindraceus) often grows right next to eborispina:

Super long terminal spines:

Typical habitat:

A perfect specimen of eborispina:

Eborispina means ivory-colored spines. Easy to see why:

Even the dead rosettes are beautiful:

More flawless specimens:

Getting ready to flower:

Long done flowering:

Another one (two actually) eking out a living squished in a crack between the rocks:

Wider view with Ferocactus cylindraceus:

Some plants were very small (with a nickel for comparison):

Small but so pretty:

And a few wider shots showing the rocky terrain these agaves call home:

I hope to explore other habitats of Agave utahensis var. eborispina if and when an opportunity presents itself. In addition to the populations in Nevada, there's a population just across the California border that was discovered relatively recently.

Range of Agave utahensis

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.

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.


© Gerhard Bock, 2022. All rights reserved. To receive all new posts by email, please subscribe here.


  1. The Agave in photo 20 shows very pretty details. It astonishing that plants survive in that tough environment and unforgiving conditions... compared with our own gardens where plants are pampered and have it so easy.

  2. I can only echo Chavli's remark about the Agave's ability to not only survive but thrive in that environment. Other than humans, are there any other threats to the species from desert critters?


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