Tuesday, May 30, 2006


At right you see the enemy of dog owners in the chaparral. This stuff goes by several common names, including “red-stemmed filaree” and “stork’s beak”. The botanical name is Erodium cicutarium, and it’s a member of the geranium family. It is an invader, not a native plant.

And it is evil. Pure, unadulterated evil. Those *$%&(@#$ seeds screw themselves into our dog’s coats, and then (if we fail to immediately find and remove them) sometimes manage to work their little pointed heads into the dog’s skin. One site describes the seeds this way:

Each “storks bill” actually is five seeds, each with the long tail tapering out to the end of the “bill”. These tails are tightly bound and make the central, elongated “bill”. At maturity, what becomes the corkscrew peels off the long “bill” and starts to curl, remaining attached to the seed. The familiar corkscrews then twist into the soil as they go through day-night cycles of wetting and drying, each time the spiral forces the sharp seed deeper into the soil. Eventually the seed breaks off, leaving hundreds of cork screws in any square meter.

Ouch! Our dogs have webbed feed, and those webs are particularly vulnerable. Debbie is so frustrated by these seeds that she’d be happy to use chemicals, radiation, or even fire to reduce our yard to bare dirt — just to avoid these seeds.

But bare dirt is a really bad idea in the chaparral, as the resulting erosion would create serious problems for us.

I managed to do a bit of research on Erodium cicutarium this weekend, and I think we may be able to help our problem a bit through the miracle of chemistry. I’ve order some MCPA and 2,4-D herbicides (the recommended brews), and we will be doing some experimentation this summer. I’m hopeful that one or the other of these chemicals will take out the Erodium cicutarium, but allow some native in its stead.

The most interesting web sites I found are here, here, here, here, here, here, and here — but there were lots more. Obviously we are not the only people who hate this noxious, evil weed…


  1. I've researched the validity of claims that the seeds of Erodium cicutarium can become dangerously embedded in animal or human skin, as I have occasionally pulled them out of my dog's fur and wondered if the screw-like shape could allow it to somehow bore into their skin. However, I can't seem to find any relevant data to support such a claim and, in fact, there seems to be a lack of any actual first hand experiences where these seeds have "drilled" or become seriously embedded in either animal or human skin.

    Furthermore, after learning in depth about the mechanism of how this plant "drills" into soil, then considering the consistency and texture of soil versus skin, it seems very unlikely that it could actually penetrate deeply into skin.

    This is because it lacks any force or pressure in conjunction with the spin.

    Spinning can allow the seed to "burrow" easily into a loose layer of topsoil (or into a crevice). When the dry seed becomes wet it begins to unroll, which pushes the seed to almost stand on its point. Then, as the uprighted seed dries, it spins, disturbing the "not so-solid on a granular scale" soil below it, allowing the seed to drop downward. There is no pressure or force applied or needed.

    Skin is not easily "moved on a granular scale" like topsoil. In fact, skin is a barrier and it requires force to penetrate. Since there is no natural pressure or force, the seed cannot move any deeper into the skin.

    Yes, the sharp point can penetrate skin, like a thorn, but like a thorn there must be a force behind the penetration (i.e. you grabbed it or stepped on it, etc.). But again, there is no force pushing the seed further into the resistant skin, so it would just spin (if it can even do that).

    As for being tangled in my dog's fur, but the shape of the corkscrew, in itself, explains why it's so hard to remove from hair or fur. It's not that "the seed is trying to drill it's way in," but rather it's just entangled in a multitude of individual strands of hair or fur wrapped around the many coils. Also, being so tangled in fur would further impede the seed and it's lack of pressure or force to "dig" or "drill."

    After considering that information and the lack of first hand accounts of any such occurance, I believe the claim of danger to be a myth.

    Do you know of a first-hand account? A person who can say they've had this specific seed become deeply embedded in either their animal's skin or their skin (more than just stuck in from the force of being stepped on, etc.)? Even better, a vet who has treated such an embedded seed of this plant?

    1. My dog just had to have several flushed out of a very infected paw. They had worked their way so deeply that nothing was visible except the wound. I have been pulling them from his undersides regularly. I’m new to the area and had no idea about this weed. Mowing it short does nothing. It’s horrid.

    2. Agreeing completely with the commentor above. Hah, almost word for word. New to the area. I had no idea about this weed. Had to take my dog to the vet for a very infected paw and pulling from undersides these godawful things stuck into his belly. And they get into our blankets and clothes. They're effing evil. I've tried mowing short. I've tried burning. I'm reluctant to use chemicals. Any time it rains, instant lawn of this stuff. I hate it.

  2. It does embed itself in the skin. A bunch of these got stuck in my long hair dachshund’s fur. I think I counted 20-30 arrows I had to yank off. A few days later his skin got badly infected, pus oozing out, and required antibiotics. This is the worst weed out there. Fast grower, loves dry soil, and is the first to bloom out of all the weeds I have in my yard. I have no idea how it grows so fast with little water. I suspect from its rosette like leaves. Sucks any sign of water before any other plant can.