Tuesday, February 28, 2012

Three euphorbias that look like cacti

Very few groups are as large and varied as the genus Euphorbia. According to Wikipedia there are more than 2,000 euphorbia species, comprising everything from annual weeds to trees. The genus also includes the many wood spurges (Euphorbia characias, Euphorbia amygdaloides, etc.) and other familiar sights like the good old poinsettia (Euphorbia pulcherrima).

Of particular interest to me are the succulent euphorbias, of which there are hundreds of species. I haven’t counted, but I’m sure I have upwards of 20 in my collection. I will do a more comprehensive post about them at a later date. Today I want to focus on three small euphorbias that look just like cacti although they are not related to the Cactaceae family (all cacti are native to the Americas while most succulent euphorbias are native to Africa). The fact that these two completely unrelated plant families look so similar is due to convergent evolution—the Wikipedia article on convergent evolution even uses the example of a Euphorbia obesa and an Astrophytum asterias cactus to illustrate this concept.

If you’ve followed my most recent posts you know that I’m making a concerted effort to better organize my plant collection and to move plants that are currently in small 3- or 4-inch containers into larger pots to make it easier to water them. This past weekend, I created two succulent bowls and I planted a Maihuenia poeppigii cactus into an unusual shallow dish. In addition, I combined three small cactoid euphorbias into a community pot:

  • Euphorbia horrida, which looks like a small barrel cactus
  • Euphorbia makallensis, which as a juvenile reminds me of a Mexican fencepost cactus (Pachycereus marginatus) although as an adult it forms mounds that look a lot like Euphorbia resinifera
  • Euphorbia mammillaris ‘Variegata’, which looks like a cartoon version of a saguaro made out of cheap white plastic

 

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Euphorbia makallensis (left), Euphorbia horrida (back),
Euphorbia mammillaris ‘Variegata’ (right)
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Euphorbia makallensis
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Euphorbia horrida
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Euphorbia mammillaris ‘Variegata’
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Euphorbia mammillaris ‘Variegata’
New growth, possibly getting ready to flower

I thought that these three euphorbias complement each other very well so I planted them together in a shallow azalea pot. Voilà, a miniature cactus garden, consisting of three plants that aren’t cacti at all.

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Miniature “cactus” garden

Maybe I should add small figurines of cowboys and horses?

4 comments:

  1. Nice, and very interesting. Two of those you can tell something uncactusy is going on, but the makallensis is harder. Do these grow more quickly than cactus?

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    1. Alan, I find myself wanting to touch the E. horrida and E. mammillaris because they look fake. The spines on E. mammillaris, usually labeled "Indian corn cob," are actually fairly dull.

      Not sure they grow faster than cacti. I've had the horrida for a year and it's only a little bigger--but it has produced a pup. Check out this monster of a E. horrida: http://northants.bcss.org.uk/nat/nat3.8.htm. It's got to be many decades old.

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  2. Yes! Bring on the plastic cowboys and horses! What better to go with a white plastic Saguaro?

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  3. Noooooooo, don't do it! LOL How about some top dressing and a rock? I love these three euphorbia's. I had a huge variegata but last winter it succumbed to the elements! Darn! It has really pretty little flowers!

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