Prairie View

Monday, August 13, 2018

War on Sandburs

In the spirit of the original web log idea (logging thoughts, events, activities in an electronic format), I will share what occupies several of each day's morning hours of late when Hiromi and I are both at home.  If you grew up summer-barefoot in this part of Kansas, the title alone probably called to mind multiple painful encounters with the plant we called sandburs or stickers.  On the farm where I grew up, we all knew where the sticker patches were, and we avoided them.  The pasture lane was one such place, except in the bare trails the cows used.  Bare feet were usually safe there. The memories I'm making now involve spotting, stooping, stabbing, collecting, carrying, and carting.

The sandbur plant goes by multiple names.  Among them are Rocky Mountain Sandbur, Puncture Vine, Goathead (Goat head), Caltrop, and Tribulus terrestris.  The Latin name suggests its nature.  It spreads over the ground and causes tribulation by means of the stiff and sharp thorns that protrude from its hard seed case.

The hours between 9:00 and 11:00 AM are prime time for attacking sandburs.  At this time of day, the pretty little yellow flowers that lure in pollinators are wide open, and the plants are easier to spot among other vegetation.  Once spotted, the next task is to locate the single tap root.  After lifting some of the branches of the spreading plant, making a quick, sharp stab underneath them toward the root severs it, and the plant can be tossed into a bucket.  Leaving any of the branches behind would also mean leaving the attached stickers to germinate another day, so disposing of the plants in a trash bin is important.  The landfill is a good place for them.

This link shows the parts of the sandbur plant in many stages, and gives many interesting details.  I learned there that the plant is native to southern Europe.  I also learned the names of two weevils that help control sandburs.  One feeds inside the seed cases and destroys the seeds, and the other feeds inside the stem and destroys the tissue there.  The weevils were imported to the US from Italy, India, and France as a means of control.  The names are Microlarinus lareynii and M. lypriformis.  This followed the accidental introduction of the plant earlier.

In past years, we have ordered the weevils from a supplier in Colorado.  They don't always survive winters here, though, so they must be reordered periodically.  Also, after the host plants are eradicated, the weevil population dies off, so they may need to be reordered for that reason.

Broadleaf weed killers and pre-emergent herbicides can help control sandburs, but each comes with disadvantages as well.  Most notably, drift from herbicides used on existing plants can also damage desirable vegetation, and pre-emergent herbicides can prevent the germination of plants that would compete with sandburs and limit their growth.  For these reasons, removal by hand is often the best method of control in home landscapes or on small acreages.

Puncture vine flowers are not the only pretty little yellow flowers we see on our morning forays.  The flowers of Common Yellow Woodsorrel--Oxalis stricta--(sourgrass or "hawssa glay" in PA German) are very similar and bloom at the same time.  The other flower that we see often in our search for puncture vine flowers is what I believe to be a low-growing clover.  It has very tough stems and almost-spherical small yellow flowers.  I'm  not sure of its exact name--perhaps Low Hop-clover.  By 11:30, most of the flowers have begun to close up.  I suspect that they have been pollinated by butterflies and other insects and they can't wait to get on with the business of seed-making, or sticker-making in the case of sandburs. 

Even with the help of the clean yellow flower color, we always miss some of the sandburs we're seeking.  We've searched all the way up and down the driveway multiple times, but today again I saw a proud plant in the driveway--yellow flowers and stickers and recumbent plant limbs all spread out to catch the sun's rays. Where was that the last time we covered this area?

We've had an abundance of rain the past several weeks.  This means that mowing must be done more often than usual.  Before each stint at mowing, we try to uproot all the sandburs we can find so that the seeds are not distributed elsewhere.  In the past 48 hours we've had more than three inches of rain, so there's a good chance that the next sandbur crop will have to be sought out among lush grass rather than seeing it growing happily in places that are too dry for most other plants. 

I've learned that puncture vine is considered an aphrodisiac in Asia.  I don't think it has that effect  when destruction is the only thing on one's mind as it is when we're on the sandbur warpath.

If you were to pass our place on a Wednesday, Thursday, or Saturday morning, you might spy Hiromi and me walking around and bending over periodically, while wearing hats and gloves, and toting a five-gallon bucket and a small hand shovel.   That will be the case at least until our hori hori tools arrive.  We've purchased several of these over the years and can't find any of them right now.  We always called them [Japanese] weeder knives.  Here's what they look like.  We also bought one like this.  We liked the comfortable-looking and durable handle and stainless steel blade with its notched tip, but it comes without a sheath and belt-loop.  I don't use a belt-hung tool anyway, so that will probably be my sandbur-digging tool in the future.  It completely lacks the solid traditional design of the tools Hiromi remembers from his early years in Japan, but I think it will work for me.  Hiromi can see to the care of his special tool while I use the less classy but more practical American knock-off.

Hori hori means dig dig.  Where sandburs are concerned, we'll be over here having a hori hori time of it till the growing season ends.  Our weapons don't have to be swords to be useful in the kind of warfare we're engaged in.









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