Wednesday, March 7, 2018

Rotting agaves don't hurt so good

When John Mellencamp wrote his song "Hurts So Good," he definitely wasn't thinking of two of his favorite agaves rotting away. That, my friends, does not hurt so good. In fact, it hurts quite bad.

Both agaves are next to each other in the same bed along the driveway. And a third one in the same bed is showing signs of rot, too.

Let's take a look. Be sure to grab a Kleenex.

Agave #1 is a beautiful specimen of Agave ovatifolia 'Frosty Blue'. It's nowhere near its adult size yet, but it has such a great presence.

Look closer.


It's impossible to miss.


It hurts, doesn't it?


It's even worse up close.


Much worse.


Doesn't look like there's much hope.


But I'm not ready to give up yet.


Here's agave #2, Agave parrasana. Not as bad. I don't think the rot has progressed into the center yet.



Agave #3 is the worst. It's my beloved Agave 'Snow Glow', a variegated sport of 'Blue Glow'. This specimen was the first 'Snow Glow' I got, and it's the biggest of the three I now have.



I could post more photos, but what's the point?

The million dollar question, of course, is this: What the heck happened?

My poor excuse for an answer: I don't know.

I honestly have no idea. As I mentioned, these three agaves are in the same bed. They seemed fine a few weeks ago, then a few days later they looked like this. Oddly enough, no other agave in any other area of my garden shows any damage. And this bed along the driveway is actually not as exposed to the elements as some others.

The only explanation I can come up is that the abrupt change from unseasonably warm weather in January and early February to temperatures below normal (hovering in the low 30s at night for several weeks) messed up these three agaves. On the other hand, Agave ovatifolia is hardy into the teens, if not below, and the other two can easily take temperatures in the mid-20s (it never got that cold). And the remaining agaves elsewhere in the garden would be affected too.

Does anybody have any idea what might have caused this?

As soon as I detected the damage, I sprayed these three agaves with Daconil (chlorothalonil), a fungicide I had on hand. Whether that helped or not remains to be seen. 

I'm fairly certain 'Snow Glow' is a goner. But Agava parrasana should pull through. And perhaps Agave ovatifolia 'Frosty Blue' will, too.

I'm not giving up hope yet, but I'm making contingency plans....


UPDATE, Thursday, March 8, 2018

This morning I removed the leaves from Agave 'Moon Glow'. They came off easily—every single one. What's left isn't pretty:


Bad news: This plant ain't coming back.

Semi-good news: Even though I saw a couple of black beetles scampering away, they weren't agave snout weevils—no anteater-like proboscis. And no sign of snout weevil larvae. But there were all kinds of critters feasting on the rotten plant tissue.

Good news: I found one pup under the rotten leaves. It had several roots of its own (always good!).

Bad news: I stepped on the pup and partially squished it. I potted it up anyway, hoping it will pull through. Agaves are tough.

Agave 'Moon Glow' pup found under the rotten leaves. I potted it in pure pumice and stabilized it with gravel.

For now, I will leave the core in the ground in hopes another pup might appear. Not likely, but you never know.

As for Agave ovatifolia 'Frosty Blue', the damaged leaves are still firmly attached. I'm hoping it will pull through. I will continue to spray it with fungicide.

Going forward, I need to treat the soil in this bed. I will first start with something "natural" like Root Cleaner. If at all possible, I want to stay away from the large-scale application of chemicals potentially harmful to beneficial insects.

19 comments:

  1. What a shame. Could it be this? Agave Crown Rot
    http://homeguides.sfgate.com/agave-crown-rot-29216.html
    https://www.gardeningknowhow.com/ornamental/cacti-succulents/agave/agave-crown-rot.htm

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    1. Yeah, it's some kind of rot. There must have been a particularly unfortunate constellation of temperature and moisture that caused the fungal pathogens in the soil to strike.

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  2. Hey, I thought Agaves were bulletproof in your climate! There must be something about that bed... more water-retentive soil? Do your best to find out before you plant anything else in their place! (If indeed they don't make it)

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    1. Bulletproof--until they aren't. I guess there's an exception to every rule :-(.

      I don't think it's a drainage issue, otherwise these plants would have died last year when it was REALLY wet. But clearly there's a lot fungal activity. I'm hoping a soil drench will help.

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  3. My first thought is agave snout weevil, although I've experienced only one case involving 2 cordylines that I thought could be linked to that. The plants were fine - and then suddenly they weren't.

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    1. No snout weevil, fortunately. The beetles I saw scampering away this morning didn't have a long proboscis like the snout weevil. But they sure liked the rotting plant tissue!

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  4. There was a night last Friday or Saturday where it rained for the entire day then dropped to 33 degrees that night in Sacramento. A dreadful combination for succulents! If they weren't shielded from the initial rain before the cold night perhaps it had to do with this?

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    1. This must have happened longer ago, but I bet it was similar circumstances that caused it. Last year was MUCH wetter and it didn't happen then.

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  5. Replies
    1. You're so sweet. Your comment made me smile. Only real plant nerds are affected like that by ill or dying plants.

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  6. That is completely baffling, considering it's been a dry winter. The 'Snow Glow' is the most heartbreaking.

    I've got some extra parrasana if you need, have the offsetting form.

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    1. We've had more rain that you. That, plus really cold nights. Somehow this led to a bad combination of factors.

      Thank you for your offer. I think the parrasana will be fine. I have a few others as well, and they're unaffected.

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  7. Oh my. Looking at these photos is indeed painful! Fingers crossed you caught it in time to save the A. parrasana and A. ovatifolia. And maybe pups on the 'Snow Glow'....

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    1. One pup from 'Snow Glow'. Which I promptly stepped on. See update above.

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  8. I'm looking at the leaves and poppies near the crowns and wondering if air circulation could be an issue here, because this is a "show" bed near the driveway you're planting it densely for impact? Looking forward to an explanation too! So sorry, Gerhard.

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    1. I thnk you've hit the nail on the head. There isn't much air circulation in this bed. Relatively dense plantings, a lime tree at one end of the bed, and a palo verde at the other. And also a lot more old leaves from our neighbor's sycamore than I realized. I try to stay on top of the leaf situation but I clearly wasn't diligent enough.

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    2. And YES, the poppies! I love them, but they can be a weed. I ripped a bunch out this morning.

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  9. I'd dig out as much soil as I could for a couple feet down and replace it with a mound of decomposed granite, or even fines, and plant into that. It will decrease the soil pathogen load and provide perfect drainage. It's what I put my plants into, and I have had no losses. I think keeping the poppies out is a good idea, they hold an amazing amount of moisture under the leaves once they get large. Sue

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  10. Wow, this is awful-heartbreaking really. I was so happy to have escaped the rot of last winter but I guess you can't let your guard down rain or no rain ! I agree that there has to be something other than just rain and temps going on here. It would be interesting to have your soil tested -maybe that would at least give you an answer-maybe. I'm glad to hear you have some replacement plants waiting in the wings.

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