“P” is for poinsettia, pyracantha, and paucity of poisonousness

Happy New Year, everyone!

As you may have noticed, 2012 got a little bogged down toward the end, and poor Mendel was woefully neglected.  But, while I abhor resolutions, I have come into 2013 with new enthusiasm, and have been reminded that I’m actually quite fond of my little blog.  So, in the spirit of things that deserve another chance, here are two seasonal favorites you may have been judging unfairly for as long as you’ve known them.

1.  Poinsettia (Euphorbia pulcherrima)

I certainly was raised in the firm belief that poinsettias were basically a festive holiday deathtrap.  Which even as a child I found a bit baffling–“Here kids!  Eat all these holiday cookies and brightly colored candies and look at these gorgeous, enticing bright red flowers that we’ve put all over the house but OMG DON’T TOUCH THEM THEY’LL KILL YOU!”

Looks...so...tasty...must...not...eat...Oh!  Not poisonous after all you say?  Just nauseating and irritant?  Fantastic!

Looks…so…tasty…must…not…eat…Oh! Not poisonous after all you say? Just nauseating and mildly irritant? Fantastic! (Photo by Scott Bauer, via Wikimedia)

It was a lot like the extremely fragile but extremely appealing delicate glass ornaments hung all over the Christmas tree, against which my brother and I perpetrated a small-scale accidental genocide over the course of several years (now the only surviving heirloom ornaments are my grandmother’s needlepoint ones, which we were unable to break).

But, reprieve!  Poinsettias, while not edible, are not actually very toxic at all.  Of the various articles I read about poinsettia toxicity, I liked Snopes’ the best.  Like many plants, they can cause nausea, so if your child eats a lot of leaves you may be in for a colorful cleanup session, and the sap can sometimes cause a rash (similar to latex allergy, from what it sounds like).  But they won’t kill you or your kids.  Or even your pets–the toxicity to cats and dogs is pretty mild (and here I have to ask–are cats who compulsively eat houseplants a thing?  I mean dogs…omnivores…fine.  My dog eats grass all the time.  But cats are strict carnivores, aren’t they?  How did evolution let this happen?  All cat owners whose pets eat their poinsettias please weigh in).

Poinsettias are only mildly toxic to cats, and can cause stomach upset.  (Photo from examiner.com)

Poinsettias are only mildly toxic to cats, and can cause stomach upset. (Photo from examiner.com)

One reason that poinsettias may have gotten a bad rap is that the genus Euphorbia to which they belong does contain a number of other toxic species (and also, I was surprised to find, a lot of succulents!  Who knew?  Since they’re Mexican natives, perhaps I should have suspected that their nearest relatives would be inventively drought-tolerant).

2. Pyracantha (genus)

This one is probably less well-known, but like poinsettias and holly, pyracantha (aka firethorn) boasts a very holiday-appropriate combo of red berries, green foliage and white flowers.  We had hedges of them around my house when I was a kid, which made prolific quantities of gorgeous red berries that I was firmly (verging on hysterically, given my predilection for consuming landscaping plants) urged not to ever, ever eat.   Though native to Asia, Pyracantha angustifolia is a very common invasive shrub in California, and several species are commonly used as ornamentals.

Pyracantha angustifolia growing wild near Cesar Chavez park

Pyracantha angustifolia growing wild near Cesar Chavez park

Unlike poinsettia, pyracantha’s relatives should have had us thinking better of it.  Pyracantha belongs to the Rosaceae family, along with many of our best-loved fruit bearing plants: apples, pears, cherries, peaches, plums (Malus, Pyrus, and Prunus genera), loquats, blackberries/raspberries (Rubus), Strawberries…anyway, yeah.  Lots of things that we like to eat.  If you look at the fruit of Pyracantha, you can see the family resemblance to a tiny apple or rosehip.


One of many clusters of fingernail-sized berries on a Pyracantha bush.

Pyracantha is not totally harmless; many species do contains traces of hydrogen cyanide (like bitter almonds and apple seeds), which renders the fruit very bitter–like a worse version of a crabapple.  I’ve been trying to determine whether the cyanide can be found in the flesh of the fruit, or only in the seeds, due to our old friend amygdalin. But so far I haven’t found a reliable answer.  In any event, you shouldn’t eat the raw fruit in large quantities (not that you’d be tempted, since they taste just awful).  Cooking neutralizes the cyanide, and improves the flavor, so a modestly popular use for pyracantha berries is to make them into jelly, or add them to other cooked fruit dishes.  Of course, given how tiny the fruit is and the poor taste, you could certainly argue it’s not worth the effort.  But the bushes make such huge quantities of the tiny berries that jelly might be worth a try if you have them in your yard.

3. (Bonus!)

If you want to be paranoid about holiday plant poisoning, your best bet remains mistletoe (which is really ruining my alliteration scheme).  We use several species of mistletoe for holiday decor, and they can contain several toxins including phoratoxin, a protein that depolarizes cell membranes and causes nausea, vomiting, dizziness, weakness and blurred vision.


2 thoughts on ““P” is for poinsettia, pyracantha, and paucity of poisonousness

  1. Welcome back! And yes, I have seen cats eating plants. Mollie, my cat growing up, used to run out and eat grass at every opportunity… then proceed to throw up in our hallway. I’ve heard it’s from some sort of diet deficiency, but who knows. Sasha nibbles on our houseplants too.

    • Hey Jen! Well I’ll be darned, as my dad says. It really is a thing. I thought it was so weird that I ended up poking around on the internet–a lot of sites agreed with you that it was a self-remedy for folic acid deficiency (although I didn’t see any data to back this up, just a lot of conjecture), and others argued that it was a purposeful way to make themselves throw up to settle their stomachs after eating something upsetting. Which I think is why dogs do it, too.

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