Large montane agaves

[Paul S]

Leading on from another thread - it occurred to me that most of the high, pine-forested mountains of Mexico I have visited have large, fleshy agaves growing there. As soon as you get peaks of 3,000m altitude, which is around 10,000 ft I suppose, you start to see some big agaves coming in. Often in conjunction with arborescent nolinas.

In the high mountains around Oaxaca and Puebla there is Agave atrovirens.



Just north of Mexico City in the mineral rich peaks around Pachuca there is Agave salmiana ssp crassispina.



Further up in the mountains of Hidalgo there are Agave salmiana ssp crassispina and with it, at Cerro La Laja (and I would guess in neighbouring lumps, too) the southern population of Agave montana.

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In the high mountains of the northeast around Nuevo Leon/Tamaulipas borders you get Agave montana again plus, a little lower, Agave gentryi.

A little further west and north in Nuevo Leon/southern Coahuila you get Agave gentryi at higher elevations.



This is in the Sierra Madre Oriental and Sierra Madre Del Sur - I have't travelled at all through the Sierra Madre Occidental as I think it is dangerous. To the south I understand the giant Agave tecta is a montane plant. But I wonder if this trend - if it is indeed a trend - continues up into the highest mountains of the USA? Is it a moisture thing?

Or is it just that I notice them and there are, in fact, large agaves everywhere? An obvious exception springs to mind - Agave marmorata is a plant of lower open dry slopes yet still get pretty huge.




Please discuss.

[KLC]

Wow Paul, that is some excellent content to start out with. I'll check back later this evening when I have the time to think about them all.

The first thing that comes to mind is how fortunate we are here in Arizona to be able to maintain these high altitude agaves with our climate.

[KLC]

I'll start with the marmorata, all of my 1g plants, and the few bigger ones I have all lean to the side like the giants in the photo. That is one huge mass of plant material there. I bet that weighs a lot, ever try to move an agave stump after de-leafing it? They weigh hundreds of pounds.

The montana and the mist gives one an idea of the climate these grow in. Being on a hillside probably allows it to take more moisture than an agave could usually tolerate yet not allow the roots to stand in soggy substrate. It looks as though getting down to that particular plant on the hillside was a little nerve wracking, one slip and down the hill you would go.

It looks like the gentryi has some pups, mine is just now starting to spit some out.

And the crassispina, Wow! I would give up a lot of my collection to have those in your photos in my garden.

Regarding tecta, Nick Macer of Pan Global Plants in the UK has suggested tecta may be a domesticate of a wide leaved salmiana taken south and propagated for pulque production. What is Nick doing these days? He was somewhat active in past forums. I've never met him except through the forums. The blogs of his Mexican travels are most interesting to read.

As Paul has said, please discuss.

[Paul S]

Nerve wracking doesn't get near to describing how I felt as I have quite bad vertigo. This is the other side of the same canyon at Cerro La Laja, with Agave mitis var albidior and Nolina parviflora I needed to torture myself as this was the site for the Agave montana x mitis var albidior hybrid and I wanted to find it. And of course it was quite a way down and right in the middle...

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And, yes, the Agave salmiana ssp crassispina around Cerro La Laja must be the nicest I have seen.

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I forgot to add a pictures of Agave montana at the La Peña site in Tamaulipas - shows the forest habitat nicely (although a lot of the forest had burnt to the ground last time I was there):

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Many of these forest agaves seem appropriate for growing in the UK, so it would be nice to know if any of the USA spp grow in similar conditions.

Nick Macer is alive and well as far as I know. We don't communicate but I understand that his interests have moved away from succulent plants and his plant hunting trips have moved to the far East.

[KLC]

Nobody else is going to comment on those amazing agaves Paul posted??? That in itself is amazing.

I can't stop looking at them.

[Gee.S]

Many of these forest agaves seem appropriate for growing in the UK, so it would be nice to know if any of the USA spp grow in similar conditions.

Nick Macer is alive and well as far as I know. We don't communicate but I understand that his interests have moved away from succulent plants and his plant hunting trips have moved to the far East.

Great shots! USA species in similar conditions? One certainly comes to mind -- A. parryi grows in relatively high elevation pine forests, but only thrives in clearings that allow sufficient sun exposure. Once trees start shading A. parryi clearings, fungal infections tend to move in.

[agavegreg]

A couple shots of my favorite high montane agave.

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[KLC]

Awesome Greg! Thanks for posting those. I knew A. montana could obtain a decent size, I've sat in on your powerpoint presentations, but I had never seen one that big. (pic 0246) Wow. Is that an oddity or do you come across those giants regularly? Can you speculate how old it is?

[Luc]

If one compare the photos showing the montanas in bloom , one can see little differences, Greg's shot shows a full bloom plant however the inflorescence is very compact and the secondary ( Don't know if it's the correct word ) branches are not well ( completely ?) developed while Paul's shot shows a dry inflorescence with a look of "christmas tree".

[Paul S]

The large bracts have fallen off the dried inflorescence which I think makes quite a difference as it exposes the stalks.

I guess this wasn't so interesting after all? Or are there no high agave rich mountains in the USA?

[Gee.S]

Paul, see Post #6, although I'll be happy to elaborate. Pics are fabulous, and anything but uninteresting. There are no areas that high that harbor Agaves in AZ. One species that does inhabit pine forests and such from about 5000' to at least 8000' is A. parryi. It grows in clearings in these forests, and starts molding when saplings grow and eclipse the sunlight they need. We have found both A. palmeri and A. mckelveyana as high as 6000'. A. palmeri grows mostly in pastures at that elevation, but we know of at least one area in which A. mckelveyana grows in juniper pinyon forest, and that is very near its type locality. We believe the high elevation pop we found may be heavily introgressed with an ancient and now extinct A. parryi pop, although our discovery of an apparent A. parryi-like domesticate some 50 miles away adds another possible wildcard to that equation.

[Paul S]

Thanks for that. Not quite the variety I imagined. I wonder what happens further east in Texas?

[Gee.S]

I don't believe Texas has elevations like that. New Mexico does, and again, I might expect to see A. parryi.

[KLC]

This is a very interesting topic Paul. Just like all of the other good topics here with little participation.

???

Post up folks, threads aren't going to answer themselves.

I dont believe there are any mountain ranges with those climate conditions here in the US that harbor those types of agaves, other than here in Az.

[mcvansoest]

I have been reading and looking with much interest but have very little experience with seeing the plants in habitat - getting a little better with the AZ stuff - usually when my dad visits, as he, now that he is 70, appears to have become the more adventurous of the two of us and I have become more of a lab rat - so it has been hard to contribute something worthwhile.

One thing I would note, is that when you look at the pics Paul posted and the plants he mentions those are all of very large to giant plants - even the A. montana appear to be gigantic compared to my little one - which granted is nowhere near mature. I would say that for the Agaves occurring at or near mountain tops here such large to giant size would be the exception rather than the rule. Ron has come across a few behemoths during his travels, but it is not like when you get to the higher reaches of some of the mountains here, the Agaves that occur are all huge.

I guess one interesting point to contradict the above contention somewhat is that A. utahensis ssp. kaibabensis is the largest growing var./ssp. of A. utahensis and does occur on the very high 8000-9000'+ Kaibab Plateau on the north rim of the Grand Canyon. It is considered one of the hardiest of Agaves, and the ssp. is also considered more wet tolerant than the others of the species, but that is relative as even despite getting snow and decent summer precipitation no one would consider that area wet, but it does have a pretty dense pine forest (and an endemic Squirrel). The soil and subsurface rocks are very fast draining - very permeable rocks near the surface, and mostly really thin soils retaining very little water.

So maybe water is the determining factor as Paul suggests...

[agavegreg]

Just some random ramblings emanating from my stream of consciousness after lunch.

The large agaves occurring at high altitudes seems to be peculiar to eastern Mexico. When you gain elevation elsewhere, the plants are not the giants that can be found in the Sierra Madre Oriental or the Sierra Madre del Sur. An exception would be in the Sierra La Laguna of Baja California Sur with Agave aurea subsp. promontorii, although not a giant, is a bit larger than the others in BCS. At high elevation in the northern state of Baja California the plants are no larger than those occurring at lower elevation. Witness the smaller Agave deserti and Agave pringlei being found higher up than the larger Agave moranii, A. avellanidens and A. shawii.

In Arizona, Agave chrysantha and A. palmeri can get larger larger than the higher elevation plants of A. utahensis and A. parryi. In Sonora, again the higher elevation plants are not significantly larger than those found lower. The biggest ones that occur higher up being A. shrevei and A. wocomahi while A. vilmoriniana at lower elevation is every bit as big as the previous two.

Further south along the Sierra Madre Occidental the two big ones that are high up in the pine-oak forest, A. maximiliana and A. inaequidens are not necessarily larger than A. salmiana which is found slightly lower on the interior plateau, while A. schidigera is definitely not a giant.

[Gee.S]

I would guess a big difference is that the high elevation locales in Mexico aren't subject to the same seasonal stresses as those in AZ. More stable climate, much longer growing season, with only wet and dry seasons to contend with -- if that.

[Gee.S]

Found quite a few 6' Agaves like this at 6000' in a juniper pinyon forest today. About as close to "large montane agaves" as we're likely to get in this part of the world.

[Paul S]

Diffficult to say without definitive scale but I'd say that qualifies

[KLC]

Nice Ron, I had never thought of our own high altitude pine forest agaves being in the same category as the Mexican species. I guess I need to expand my horizons a bit. We probably wouldn't get the same result growing the same plant in shaded conditions down in the city.

[Gee.S]

We've seen plenty of A. chrysantha × A. parryi hybrid pops before, but usually they result from parryi pops bleeding into marginal chrysantha habitat. This is chrysantha bleeding into solid parryi habitat, and these guys are BIG!

[Agavemonger]

Southern Texas has the semi-giant Agave havardiana in the Chisos Mountains, also in association with Nolinas. The plants range from about 1,200 to 2,000 meters in elevation. The largest plants can approach two meters in spread, and perhaps up to a meter and a half in height.

Agave havardiana is the only species in the United States that borders on huge, being easily well over twice the size of the largest Agave parryi plants the Dude and I have seen in our travels. There are some hybrid plants a little further north, in the Davis Mountains and environs, that vary between Agave neomexicana and Agave havardiana, but they are generally smaller than the Chisos Range Agaves, which I consider "pure" Agave havardiana.

There are purported to be other "Agave havardiana" plants in disparate places near the Guadalupe Mountains, but we have yet to stumble on any.

The Monger

[Gee.S]

Agave havardiana is the only species in the United States that borders on huge

A. chrysantha can grow to impressive proportions, and this A. palmeri is 12' across. Both chump change next to the true giants, of course. I haven't seen an havardiana anywhere near that size, though I would certainly like to. I'd guess the biggest ones must remind of ovatifolia.

[AGAVE_KILLER]

I believe the important distinction is population average large versus subject-specific large. A one off here or there is distinct from consistently large within population.

Another example of population average large at elevation would be the giant parryi form in the pass east of Miembres. haven't visited, but monger and I have plans to.

Awesome plants, thanks Paul. Your photos and trip reports on forums and at oasisdesigns have heavily contributed to my understanding and interest in these species -- not to mention my southerly wanderlust, for which my wife curses your name.

[Gee.S]

Well, it isn't as if those are freakishly large plants on an individual basis. Each represents a substantial population. A. palmeri regularly reaches and even exceeds 2-3 meters across much of its range. There is a large area in central AZ where A. chrysantha reaches 3x - 4x its normal size. The example pictured above is the largest we saw, but there are thousands of very large Agaves there -- the most massive Agaves we have seen in habitat by a wide margin. Unfortunately, this pop remains all but completely unknown due to extreme accessibility issues. Just ask Peter about Rug Rd. The mere mention is likely to have him clutching his heart. We actually drove more than 100 miles out of our way to avoid turning around and negotiating that road a second time. In any case, these are not from montane habitat.

Re: A. parryi -- how giant is giant? We've seen spots where huachucensis reach 4' across.