Monday, March 09, 2009

Tree Cholla: Plant of the Week

If you're one of those people who rescues stray kittens, perhaps you'll understand the impulse that led me to bring home this bucket o'cholla last week. A new neighbor had apparently been inconvenienced (or perhaps attacked) by these plants outside his front door, and chopped them all down. Then he threw them across the street on untamed property. (Okay, a gulch in a horse pasture; but it's a nice gulch!) I couldn't help myself*; now I've inherited a moral obligation to give them another chance.

My motives weren't entirely altruistic. Once you get past their forbidding exterior, these are more than acceptable landscape plants, in my view. (I'm not sure kids would be as wary of them as the dogs are, but they too would learn in time.) That they are alive was confirmed by the fact that, though sprawled horizontally for a week or two, the tips had already turned up, toward the light. It's tough to kill a cactus, but it's always easier to do it with kindness than with neglect.

This cholla, Cylindropuntia imbricata, is the only species of its type to occur naturally in eastern Colorado, as far as I can tell, though we are surrounded south and west by states with many more species. (C. whipplei occurs in a few southwestern counties.) As you can see, it is not reported from the county (triangle) where Foothills Fancies is based. Like coyote gourd, it is another outlier, or perhaps an introduction, in these more northern sites. (Map adapted from USDA Plants Database.)

Kingdom Plantae – Plants
  Subkingdom Tracheobionta – Vascular plants
    Superdivision Spermatophyta – Seed plants
    Division Magnoliophyta – Flowering plants
      Class Magnoliopsida – Dicotyledons
        Subclass Caryophyllidae
          Order Caryophyllales
            Family Cactaceae – Cactus family
              Genus Cylindropuntia (Engelm.) Kreuzinger
              Species Cylindropuntia imbricata (Haw.) F.M. Knuth
                – tree cholla

By the way, I've never actually heard anyone call it tree cholla, but maybe that's because it doesn't actually occur around here. Our other source, Weber's Colorado Flora, calls it "Candelabra Cactus." I suspect the "tree" name translates an older scientific name, Opuntia arborescens, given it by George Engelmann himself.

Here's what the one in my yard looks like today. I know, kinda droopy and repulsive. The yellowish fruits hang around all winter, until they rot or new growth pushes them off, I guess.

Ahh, but this is what it looked in recent memory, given an appropriate spring/summer.

Then, every bee and nectar-loving winged thing anywhere in the vicinity was happy, very happy, with this plant. For its ability to attract pollinators alone, this plant is worth having in your yard! Click to see insects at work.

Back to our bucket—here's a quick lesson in cholla anatomy. These branches are, of course, main stems. Leaves are briefly apparent only in season. Spines come in clusters at locations called areoles, usually at the end of bumps called tubercles. The fuzzy look to the areoles relates to the presence of tiny glochids, which our source** says are "inconsequential" here. (On other Opuntia species, it does not pay to dismiss the glochids so lightly.) One does not handle these without gloves or, preferably, tongs. Long-handled tongs.

Here's a bug's eye view. If you'd like one of these cute fuzzy stray kittens for your very own, call me!

Now I just have to go back and finish off the Myrtle Spurge that's escaping that same neighborhood yard!

* I have trouble with the idea that living beings are disposable; hence my difficulties with Poinsettia as well.

** Colorado Flora: Eastern Slope, W.A. Weber, 1990. But see also Catalog of the Colorado Flora (which eludes me at the moment) and Flora of North America.


Watcher said...

Great post- I LOVE tree cholla! Actually, I think what we get in Southern UT is Buckhorn or Whipple cholla. I see a lot of 1 or both when I'm down South; I'm determined to figure out which is which when I go back down in April.

Be careful with the spurge. I read/heard so many stories when researching that post I did last week.

Anonymous said...

Thanks, Watcher... I don't know why they call this one "tree cholla" as that name applies equally well to the others. I tend to just stick with "cholla." You're lucky to have more of them; good luck with the ID.

I got most of the spurge last year, just a few plants left. I think the new owner is going to rip out what's in the yard, too. Great news! (And yes, I'll be careful!)

Anonymous said...

This is one of my favourite cacti- hardy and quite conspicuous! You don't neeed to knee to see it in detail, as for many hardy ones that are dwarfs. That happy, tall exception is growing perfectly in my yard in Bucharest, Romania, a climate like SE-Colorado, only wetter. The tallest is over 1 meter high and I expect almost 2 meters in the future. I keep plants from NM, KS and CO- from CO I have 4 locations with magenta flowers and a rare white-flowered clone!
Always nice to see people appreciating their own native treasures! Loved the story and photos!

Sally said...

Fabian-- thanks for your kind comments. I'm glad to hear you're enjoying this species as far away as Romania!

As a cactus fancier, you might also enjoy this post.