Friday, January 22, 2016

Preliminary winter damage report (January 2016)

In previous years I went overboard when it came to covering plants on nights with temperatures below freezing (see here: 2011 | 2012 | 2013). This winter I decided to relax and cover only one plant: my Agave attenuata ‘Boutin Blue’, which starts to shiver when temperatures fall into the 30s.

While we hit 32°F six times in December, we only dropped below it once: on December 27. That was the day I headed out on my trip to Southern California and Arizona. I left our house at 6 a.m. and the thermometer in our backyard read 29°F, which meant it was a degree or so colder in the front yard. Indeed, the official low for Davis was 28°F—a balmy night in many parts of the country, but a c-c-c-c-cold one here.

For some reason, 28°F seems to be a magical number for many succulents. They’re fine at 30°F but start to show damage at 28°F and go into a serious tailspin at 25°F or below. The photos I’ll show you below bear out this observation.

To put things in a perspective, while my not-bothering-to-cover-things experiment was partially successful—plants I thought would get damaged at 28°F didn’t—other plants did. However, the damage appears to be cosmetic only, and all affected plants should survive.

Let’s take a closer look.

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Agave desmettiana ‘Variegata’, one of many offsets from the plant that used to be next to our front door but flowered and died last year.

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It’s in a large pot under the bay trees in the backyard where it should have been protected enough. It has some pretty unsightly cosmetic damage and will live However, I’m done with this particular agave and will replace it with something else.

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Agave desmettiana ‘Variegata’ bulbils with leaf damage. Two trays around the corner have zero damage. Go figure.

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 Agave desmettiana ‘Joe Hoak’, growing in the ground between our house and our neighbor’s

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Again, only minor cosmetic leaf damage, but I’m annoyed at myself because I could have prevented it altogether by throwing a frost cloth over the plant

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The black spots will be visible well into the summer, reminding me to be more vigilant next winter

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Graptopetalum pentandrum ssp. superbum. This level of damage is surprising because I don’t remember covering it in previous years. But it, too, will live.

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The aeoniums in the backyard only sustained minor damage (like this). They’re up against the house and fairly well protected.

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Kalanchoe beharensis with significant leaf damage. This doesn’t come as a surprise since this species (like most kalanchoes) is very frost-sensitive. Still, it will live and push new leaves.

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Agave potatorum ‘Shoji Raijin’ with enough cosmetic damage that I’m officially evicting this slow-growing dwarf cultivar from my collection (it’s not a favorite of mine anyway). Agave potatorum once again proved its wimpiness.

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The closely related Agave isthmensis in the front yard fared a bit better, with only a few leaf spots. The volunteer jade plant (Crassula ovata) seedling on the left has leaf damage, too…

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…while this much larger jade plant next to the driveway (blooming, no less!) is completely unharmed. It could be because of a temperature difference as minor as 1°F.

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Two pachypodiums that are losing their leaves (but not their lives): Pachypodium eburneum (left) and Pachypodium geayi (right)

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This Agave pygmae ‘Dragon Toes’ took the worst hit. I had temporarily moved it from the front porch to the front lawn so it could get washed off by the rain and then forgot to move it back. I think the front porch would have offered just enough protection.

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While ‘Dragon Toes’ will live, I’m really bummed by the extensive leaf damage. I may get rid of the mother plant and start over with one of the pups.

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Most of my agaves (like this Agave applanata ‘Cream Spike’) are just fine, thank you—completely unfazed, in fact, by that little bit of frost we had at the end of December

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This Cuphea ‘Vermillionaire’ flowered all the way into December until it was felled by the frost on December 27. But I see some green along the base so it should come back.

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I fully expected this red bird of paradise (Caesalpinia pulcherrima) just behind the Cuphea to lose its leaves (it always does around 30°F) but it’s hanging on to them this year. That’s a good sign. Maybe it’ll even flower this summer.

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The only aloe with damage is this Aloe dorotheae. It doesn’t look damaged but the leaves are suspiciously soft. Time will tell. I knew it was risky to plant it out in the open outside the front yard fence. It’s not a hardy species.

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This newly planted Russelia equisetiformis got knocked all the way to the ground. An established plant not far away has no leaf damage. Go figure (my phrase of the day).

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Most succulents are doing very well. The Aloe ferox above is pushing its largest flower stalk ever.

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The emerging flowers on my Aloe ‘Moonglow’ are undamaged

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Even this fan aloe (Kumara plicatilis) is fine. The desiccated leaf tips are common in potted specimens in our climate; they’re caused by drought and/or salt build-up in the soil. This plant will go in the ground in the spring so the leaf-tip problem will hopefully go away.

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The biggest problem right now is the leaf litter (from a Bradford pear tree in the photo above) that is partially covering many succulents. I’ll work on removing the dead leaves this coming weekend. Mold is beginning to form under them, which could disfigure the succulents and/or cause them to rot.

January weather update: So far every night in January has been above 33°F. The next 10 days look to be frost-free as well. I’m going out on a limb here, but I think we’re out of the woods as far as cold weather is concerned.

19 comments:

  1. Some of this is ugly, some is just scary -- like the Kalanchoe beharensis and pachypodiums. I'm glad to see you relaxing a bit though, except with the "I'm done with this" agaves. Can't grow everything, right?

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    1. I'm trying to be more relaxed about plants dying. More opportunities to plant other things!

      And no, we can't grow everything and I should stop trying.

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  2. I think the coldest weather is past also--true El Nino storms are warmer.

    Interesting to see the cold damage. If we ever actually get some frosty weather here, I'll know what to look for. Kumara plicatilis in the ground gets brown tips here in the summer when not watered sufficiently, though the drainage here is very sharp.

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    1. Interesting to hear that Kumara plicatilis gets brown trips in your climate as well. Some people say absolutely no water in the summer because it's a winter grower but I don't think that would work.

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  3. I'm with you Gerhard, we may get some light frosts here and there but I think the 20's are over for the season. I'm more worried about rotting plants than freezing plants at this point !

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    1. I'm starting to worry about rot as well. I haven't noticed anything bad yet but I'm aware of the possibility. Fortunately, it looks like we'll have a few dry and sunny days. Just what we need.

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  4. My 'cream spike' has been in the ground for 2 years, uncovered, and we get a bit colder than Davis, so it seems pretty hardy. I'm not sure we're done with frosty nights in the desert yet, but hopefully there will be more rain too!

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    1. I think 'Cream Spike' is hardy down to the high teens, maybe even a bit lower with some protection.

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  5. So I guess I wasn't the only one doing a little cold weather experimenting. Sorry to see so much damage, although with the exception of 'Joe' it sounds like you're not too upset about it? I've got a few Agaves that need rotting arms amputated, if we could just get a string of dry days in which to do it. Ugliness.

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    1. Oh well, you live and learn. I'm trying to be sanguine about it.

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  6. Your post is another reminder of how spoiled I am in not having to deal with "real" cold. The only reaction to our cold I generally see is some pink or red color.

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    1. You guys in coastal Southern California are pretty much living in paradise as far as gardening is concerned :-).

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  7. I'm worried about rotting, too -- so much rain, day after day, here in the Bay Area. Question about the red bird of paradise: I brought one back from Scottsdale 2 years ago and it has grown very little (I have it in a pot). What can I do to help it along?

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    1. Nancy, mine came from Phoenix as well. Funny coincidence :-)

      I'm not an expert on red bird of paradise, but from what I read, it likes a lot of heat (and water in the summer). Supposedly it's a fast grower once established. Emphasis on the latter. Maybe this year (year 2 in the ground) it will thrive and bloom, instead of just exist.

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    2. I almost threw it out last June, before last summer's trip to Tucson, but when I returned several weeks later, it had sprouted foliage again and seemed to be willing to live. Now, it's barren again. Sigh! btw, love reading about your adventures!

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    3. It's normal for it to lose its leaves in the winter. It's already proven itself to a tough cookie. It'll come back!

      More adventures coming. Always :-).

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  8. You are being very sanguine about your losses, Gerhard! I had one of my favorite variegated agaves develop some bad rot with our heavy un-El Niño-like weather this winter, and I'm afraid it is lost.

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    1. Oh no! Losing your Agave weberi 'Arizona Star' would be a tragedy.

      Speaking of 'Arizona Star', I just noticed some brown spots on mine, possibly from the cold. Which would be a surprise because it "only" got to 28 or 27°F and 'Arizona Star' is supposed to be hardy to 15°F.

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  9. It is good to relax and it is good to experiment. The hard thing is unlike perennials the damage will show for a long time. We haven't gone below 32 yet....but every few years we get in the mid twenties. Weather, what are ya gonna do!

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