Great banding on this Agave sobria

[mcvansoest]

I had not taken a good look at this Agave sobria (or aff. sobria given that it was grown by KLC from seed originally identified as A. gigantensis, which it clearly is not) in a while, but this morning noted how every time I do look at this, this plant is looking better and better. The cross banding on it is getting better and better.
It took a while to adjust to full summer sun, but is now completely happy. So far it has been solitary and a slow grower. It gets very little water.

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[Agavemonger]

Very nice, Thijs; looks like maybe this plant might have a slight bit of variegation in a couple of those leaves on the left side.

I can't seem to figure out what those black plastic rings are in the ground: could you enlighten us?

The Monger

[Stone Jaguar]

Very neat!

[mcvansoest]

Monger, I see what you are saying I will check it out because I had not noticed that before.

The rings are the bottoms of wine bottles that for a while I was using up side down as bed dividers mainly to keep soil from moving around as I was filling in the bed.
This is a long slightly raised bed in front of my west facing wall of death - the low angle sun beats down on it really badly in summer causing incredible heat reflection that really fries the plants, so it has been fatal or near fatal to many many plants I have tried there.
As you can see it has a lot of leaf debris in it - the neighbor has a lot of oleander planted on his side of the wall and those are very messy. but they do provide some overhead protection.

The little A. kissho kan is only just hanging in there. It gets beaten up really badly in the summer. I am hoping that it will adjust though as it does look a little better each year. There is also an A. parryi var. truncata that finally appears to have settled in. Other Agaves that have worked in front of that wall have been Agave asperrima, sobria ssp. frailensis, a regular A. parryi, and an Agave chrysantha.

Things that work best there are prickly pears and chollas... and some other bigger cacti.

[Gee.S]

That sobria has potential, love that banding! I have a death wall so bad, I wasn't sure anything could live there for a time. No Agave could manage it, tell you that. I wound up resolving it with Yucca faxoniana, Opuntia aciculata, and a Fero. Lesson learned. Certain Yuccas don't even blink at sun/heat issues this side of a flamethrower. And the Opuntia couldn't being doing better. The Fero however, is managing nothing more than OK. That Yucca is looking pretty good, I just noticed. It's about 4.5' tall.

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[Azuleja]

Very nice! I have a couple of KLC's seed grown A. sobria too. They're lookers. I have one under cover and one in the open because he said they rot very easily if over watered. Kind of testing the waters to see if they will tolerate it here.

[mcvansoest]

Ron, that yucca is looking very good. You mentioned that Yucca and another as super good in the hot sun to me before. I have been meaning to try and find that post so I can put those on my wish list, as I am trying to get rid of a few things I have growing there...

All the fero's I put in front of that wall have not done very well. I lost 3 to rot and have two remaining there that have been OK, but just not done much in terms of growth.
I have a couple of stenocerei that are doing well, a Trichocereus terscheckii that took a while to adjust but now seems to be happy as it has started growing well - it is up to 4ft now.
but other than that a lot of chollas and prickly pears and the different versions of tephrocactus articulatus. So adding some yuccas will be good.

Azuleya, I have a got a few more from KLC that I am growing in pots for a little while longer but I think they will mostly end up there as well. I have one under quite a bit of shade and that is looking way more green, which may explain the original confusion with A. gigantensis.

[KLC]

Cool Thijs. Agave sobria at the Sonoran Desert Museum was somewhat of an inspiration for me early on, I was intrigued by their size and ability to grow without any irrigation whatsoever. I have one out in the front that is starting to get some mass to it. I've got a few boxed up that are going to San Antonio, Tx. in the next few days. We just had a few days of intermittent showers, I need to go out and see what the guys look like in the nursery tomorrow. I have found it necessary to withhold water completely from mid-December through about March to avoid rotting the leaves off of them. They actually look good when they are a little shriveled and dehydrated. This is one plant on a short list that will take full Phoenix sunshine with no irrigation and 6 months later take the coldest nights without a blemish.

[Paul S]

Ron, are you sure that is Yucca faxoniana? The leaves look far too narrow and crown far too dense. Looks more like torreyi or similar.

[Gee.S]

I am absolutely not sure. Here is a pic from six years ago, shortly after I brought it home. I picked it up from a nursery that had more different kinds of Yucca than any place I've seen, perhaps 20. From what I've been able to glean, taxonomic obfuscation abounds between the likes of faxoniana, torreyi, and treculeana, and the three names are at least occasionally used interchangeably.

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[Bananaguy]

Mcvansoet great looking Agave and bed looks good anymore pictures? Love the colors and leaf texture.

Gee nice looking bed as well and love that cacti that resembles micro daisy’s.

[KLC]

Some of mine from same seed batch.

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[Stone Jaguar]

Mac:

Wondering what - if any - special feed regimen you have? I have found that I can induce faint banding in normally non-banded agaves with relativel high levels of Ca and Mg and low levels on N. This micro feed regimen also enhances the blues in normally glaucous agaves, so big fan of this trick. I do not have anywhere near the light intensity you have, so am beginning to suspect that key minerals in substrate + genetics + adequate light intensity = banding.

In any case, again, that is a badass-looking plant.

J

[KLC]

I have agaves that will form bands even under 50% shade and in nutrient poor growing media. I have paid much attention to it and have come to the conclusion that the banding is the result of growth spurts brought on by brief introductions of water. The banding is just the absence of the waxy coating on the leaves in some areas. I've mentioned this in another thread so here it is again. When an agave is watered it takes up moisture and stores it in the leaves causing them to swell and put pressure on the emerging core, this friction rubs off the wax coating and makes a "band". As the agave dries up again the leaves will lose some of their water mass and relax the grip on the still emerging core and allow the wax coating to stay intact. This repeated wet/dry condition creates the bands that you see. I only irrigate my agaves once a week or less, sometimes every 2 weeks. I have put markers on some of them and the banding does indeed coincide with their water schedule. Don't overthink why the bands are there.

[mcvansoest]

J,

Thanks!

Note added: As I was writing is KLC just posted his insight - so some cross posting going on.

I do not remember if I ever intentionally fertilized that plant, I certainly have not in recent years. If I did it would have been with one of the Bayer protect and feed solutions that I used to use for my anti weevil treatments - not sure what the nutrient levels in those are but I doubt there is anything special. These days I go with cheaper solutions and/or granules that do not come with fertilizer added. What I can say is, that the soil in the bed probably contains a good dose of broken up Caliche and that will likely be high in Ca and probably also contain a good dose of Mg. On top of that I have found shards of broken up cement in there. During the original round of planting, I amended the bed with a bunch of bags of cactus soil, some clay rich soil (which in hindsight I regret as that probably is the cause of why several of my big rescued ferocacti rotted after some heavy rains), and some bags of paver sand. So relatively poor in nitrogen, though there is plenty of oleander leaf debris... but I am not seeing that convert into any kind of useful compost with any speed.

I realized today that I also have Agave angustifolia in that bed - a pup I got from Ron's plant a few years back. That plant has also taken the sun like a champ, but no obvious banding on that one.

I am planting some new plants this weekend, and aside from some prickly pears, I am putting the Agave sobria (pseudogigantensis) I got from Greg Starr a few years back in that bed. It has been under 50% shade cloth and is definitely showing quite a bit of green, and not much banding at all, so it will be interesting to see how that one develops (though this coming summer I am sure it will have to live under some shade cloth).

I think your recipe for developing banding sounds like a good one, though, like KLC, I have also wondered about the influence of watering frequency. None of my plants are on drip irrigation so while they are watered regularly especially in the hot summer months, they still get water episodically say once a week or once every two weeks rather than a higher frequency but maybe less water at a time that is often associated with drip systems. In the community garden where I am working on establishing a xeric bed, the bed will have drip irrigation so I will have the chance to see if plants develop any differently.
In my experience, light intensity definitely plays a part, as my shaded plants definitely show the banding less, even if they are genetically predisposed to developing it. Possibly, a good amount of neglect may also help, but now you have me curious as to the composition of my soil... hmm, I do manage a geochemistry laboratory.

Keith, those are looking good! I am getting the distinct impression that these sobrias are better in the ground plants than potted plants. I have another couple that I got from you during my last visit and while they are fine, they definitely have languished during these last few months and it has not even be wet or cold... One of those is going to the community garden, while the other is going in my front yard area where full sun is all that there is to be had.

Bananaguy, I will try to come up with some more pictures of the bed, but since it feels like a continuous 'in progress' area to me, I never take (m)any pictures of it.

Another plant that has done great there, but got beaten up really badly last summer, is Austrocylindropuntia subulata. It is still doing great, but it has some pretty ugly sunburned sections, that it will take a long time to grow out of.

[KLC]

Yep Agave sobria does not like wet or cold. They will also grow magnitudes faster in the ground. These are in the top 3 or 4 favorite agaves I have.

[Gee.S]

Just want to point out that some Agaves are more equal than others when it comes to banding. A. angustifolia doesn't do banding, at least not that I've seen. Neither does A. parryi. When we do see slight banding in A. parryi, I see it as an indicator of introgression. OTOH, A. sobria is very prone to banding, along with A. deserti var. simplex, A. colorata and others. A chrysantha can be heavily banded, but not so much with A. palmeri. All that said, it is tough to get nice banding in garden plants, so nicely done!

[Stone Jaguar]

KLC, at the risk of continuing to “overthink” the enhancement of banding, if I read you correctly, it is child’s play to induce banding in agaves by marking hard watering stops between irrigation, at least in the desert. While I admit your theory would seem to have merit, once again, correlation doesn’t necessarily imply causality. If you are right, than everyone in AZ and the CA deserts can “band” those species that are predisposed to show contrast patches on their leaves via manipulation of water. Is this really the case for others on this forum? Gee’s comment above suggests that it is not quite that simple.

Again, I suspect that there is a complex interplay of genetics, environmental factors, substrate structure and fertility as well as access to water that makes some plants more vividly banded than others. Indeed, the plants you show that are from the “same seed batch” (sibs?) as Mac’s are rather unremarkable to my eye, so, to cut to the chase, you haven’t convinced me at all.

To clarify, when I say “induce”, I mean that over the past semester I have lifted faint bands on agaves not known to band and with previously concolorous leaves...in bright shade, with regular watering, but with nutritional tweaks, including low N, high K and high Ca and Mg.

[mcvansoest]

J,

Do you mix up your own batch of fertilizer or is that low N, high K and high Ca and Mg something that is available for sale somewhere? I'd be interested in seeing how adding that to a few plants here might affect the appearance of banding or not. For example if adding that to a potted plant in my shaded area that should normally get banding but has not yet or only poorly will change its appearance.

[Stone Jaguar]

Nutricote 10-10-17, available from East coast suppliers as an orchid and bromeliad 270 day time release + encapsulated gypsum (Encap) + granulated dolomite at label rates for soil mixes, which are at least 50% hort grade pumice.

This is base mix. I supplement feed with CalMag (available online) at 5 ml x gl every three weeks for potted plants during grow season. Again, the beautiful contrast banding your plant shows that almost looks like that on some extreme zebra made me curious as to whether there was a lot of calcium and mag in your substrate.

Good luck with your experiments!

[KLC]

You can believe what you want and I'll believe what I want. What causes the banding isn't really that important to me. Im sorry the photos of Agave sobria I posted were unimpressive. I didn't post them to try and outdo anyone. I don't claim to know much of anything, in the past I have even referred to myself as somewhat of a village idiot. To save myself the embarrassment of posting something that is as outrageous as my theory on banding, I'll let you do all of the talking from now on. It seems you have the desire to be the smartest one in the room.

[Spination]

Banded or not, the two examples in post #12 are fantastic looking plants. I love the silver blue color, and just overall great looking specimens.

[Gee.S]

Banding does seem an aspect of being glaucous, since only glaucous Agaves demonstrate banding. (Please jump in with any examples that counter that point.) And my experience suggests that in general, cultivation discourages banding. I've seen gobs of cultivated A. zebra, for example, and not a one has demonstrated prominent banding. Different substrate? Probably. Different watering regimen? Almost certainly.

[Spination]

I would tend to agree, as I've seen plenty of your habitat and water stressed examples with awesome banding, while cultivated specimens not so much. Surely, it is a function as well of the glaucous, waxy-coated plants that demonstrate that capacity. As such, I still believe as I did when I first read Keith's explanation and theory behind it, that it makes a lot of sense to me. The cultivated vs non cultivated aspect of it does suggest that availability and frequency of watering is a major component, since most cultivated plants surely get watered much more than in habitat.

Anyway, it's possible too that one specimen might be more able to band than another of the same species, which could suggest a genetics or chemistry aspect of it too.

[Azuleja]

I've definitely noticed banded growth after watering and I've also had water/rain wash away the beautiful glaucous coating on my A. murpheyi. As already mentioned, A. colorata is another that seems to band pretty reliably.