Monday, June 15, 2020

The weed I love to hate

Weeds are a fact of life for a gardener. I'm not obsessive-compulsive about weeding; in fact, I'm quite tolerant towards some (Mexican needle grass, I hope you appreciate it). But there's one weed that drives me bonkers: spotted spurge (Euphorbia maculata). It's an annual that goes away in the fall and doesn't come back until late spring. But when it does, it's seemingly overnight—and it's everywhere, especially in inconvenient spots like this:


That's my prized Ferocactus rectispinus, a formidably armed barrel cactus. As you can see, the spotted spurge has staked its claim in this pot.


Reaching in with your fingers and simply pulling it out is not really an option. These spines mean business!

This is where long tweezers come in very handy. I grab the stem and twist the tweezers until the roots lift out of the soil. This is much easier when the soil is wet, so I watered this pot thoroughly the day before.


Ten minutes later, I had a nice little pile of extricated spurge. A few times, the stem broke before the roots came out, but that's OK. I don't think spotted spurge regrows from the roots.


And here is my Ferocactus rectispinus in all its spurge-free glory:


Spotted spurge is part of the massive euphorbia family. The Euphorbiaceae is the fifth largest flowering-plant family and includes members as diverse as the rubber tree (Hevea brasiliensis), the world's most important source of natural rubber, the Chinese tallow (Triadica sebifera), a widely grown ornamental tree, the castor bean (Ricinus communis), and of course the genus Euphorbia proper, which encompasses everything from the poinsettia (Euphorbia pulcherrima), the woody spurges (like Euphorbia characias), the many cactoid euphorbias so popular with succulent lovers, to countless pesky weeds like my behated Euphorbia maculata

What all species in the genus Euphorbia have in common, aside from the milky sap, is their special flower structure. The flowers (called “cyathia”) are reduced to only the parts that are absolutely essential for reproduction. Our pesky spotted spurge, which is native to the eastern U.S., is a prime example:


As much of a pest spotted spurge is, it deserves respect for how it's evolved to maximize its chances of survival. The growth cycle from germination to flowering and seed production is just one month. Let that sink in! 

Each plant produces thousands of seeds, which can germinate instantly if the conditions are right (like they are right now) or lay dormant for years. The seeds are tiny (no more than 1 mm) and have hairs that allow them to stick to anything from animal fur to clothing, even shoes, making it easy for them to hitch a ride into the big wide world.

Basically, once you have spotted spurge in your garden, you'll always have it. That's just how it is. 

What's your most behated weed?


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15 comments:

  1. OMG I hate that stuff. But Oxalis is my Enemy Number One. At least the damn spurge goes away for awhile, but Oxalis is a year round pest -though worse in spring and summer.I has had the gall to come up in the middle of my Bouteloua -how does one extract oxalis from the middle of a grass ? Hate it .

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    1. I have ongoing battles with oxalis as well. There's no getting rid of it, no matter what you do. I have it growing in a mat of Dymondia margaretae!

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  2. I share your hatred for that particular weed, which is also everywhere here - pulling it out of my gravel-covered paths and the wood mulch under my Magnolia is a tedious exercise. Oxalis is also a pest but somewhat less widespread. The clover that apparently came in with topsoil I imported after we tore out our front lawn is also becoming a pain in the neck, although at least it's reasonably attractive and it feeds the soil.

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    1. Oxalis is my #2 most behated weed.

      I don't have any problems with clover, but after spurge and oxalis, I could live with clover, I think.

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  3. That is one seriously armed cactus. A great tool I use for weeding in challenging places is a hemostat: has handles like scissors with a long nose that grips at the end. There are a lot of weeds on my hit list but the top two would be dandelions and thistle. Reading your description of the euphorbia was like a description of the dandelion too.

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    1. Agreed! I have a set of hemostats as well. I use both hemostats and tweezers interchangeably--basically, whatever is at hand.

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  4. Well thank god I don't have it! I'm with Kathy on my most hated weed, oxalis, specifically the dark leaved variety. Evil evil stuff.

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    1. That's why I have such a hard time planting ornamental oxalis. The only oxalis I grow on purpose (and in a pot) is Oxalis palmifrons.

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  5. I have that same murder cactus! I let my weeds dry out and shrivel in the heat for a few weeks. Does your plant also have the ants that go for the nectar-producing glands? I've finally decided that since they're in a symbiotic relationship with the fero, I won't try to get rid of them... yet.

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    1. I don't have ants on ferocactus, but I have them in the soil. I let them do their thing unless they farm aphids!

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  6. Hard to keep up with weeds. They always seem to have an advantage, no matter how hard I try or how many hours I spend on my knees trying to get rid of them. Interesting information about euphorbia. Good to remember that the milky substance is poisonous and could damage your eye sight if it gets in your eyes.

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    1. I'm not allergic to the milky sap of euphorbias (at least not on my skin) but some people are. So it's always good to be careful.

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  7. Right now I can't think of a more diverse genus than Euphorbia. Anyone care to comment on that? Here the nuisance is Euphorbia peplus, but the most fecund weeds are Cardamine hirsuta (hairy bittercress) and fireweed. Other plagues include dandelion, German chamomile and horsetail.

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  8. While I try to avoid pesticides, I throw in the towel and reach for the Preen for all the succulent gardens I take care of. A sprinkle three times a year and the plants remain weed free. It's not cheap, but it works and I am getting too old to crawl around on the ground with tweezers, trying to keep up with the spurge. Preen's only downside is that it MUST be applied BEFORE the weed seeds germinate, it will not affect plants after germination.

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  9. Was just pulling some of that spotted spurge this morning. Hate that stuff.

    Another hated weed Euphorbia is E. peplus.

    I pull all the castor bean plants on the roadsides and in the local park because it is classified as a noxious weed in our county. Was amazing to see it's red-leaf version during the Portland Fling being a well behaved ornamental. Frost isn't always bad...

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