Blast! Puncture Vine

I had just filled up the tires on the used mountain bike I bought at auction, and climbed aboard for my maiden voyage on its frame. Visions of zipping along my country road with the wind sweeping across my face pleasantly played through my mind. The voyage lasted just fifty yards of my long driveway at Lamar. Thinking nothing of cutting the corner by the tree, I spun across some low spreading weeds, after which I began to hear a clickety-click sound as if I was driving with studded tires. Moments later I felt the front end of the bike sink and with it my sense of excite- ment until both the rim and my spirit scraped ground.

Blast! Puncture vine.

In one of my past "job lives", I worked for the Skamania County Noxious Weed Control Board. It was here that I became inti- mately involved with weed identification and weed con- trol. I headed up a program targeting Japanese and Gi- ant Knotweed-a terrible European invasive that has taken over stretches of sev- eral western Washington waterways, most notably the Skagit River. While these two invasives top wet Washington's list of plant pests, neither in my mind compare to our dry side's vicious vine.

Puncture vine, (aka Goathead, for the shape of its sharp, spiny fruit), is com- mon in loose, sandy soils in dry climates, as well as in compacted soil such as along roads or in playgrounds. It needs very little moisture and will outcompete most other plants in areas where water is scarce. The University of California system observed a single puncture vine plant producing 576,000 goatheads.

It is native to the Medi- terranean. It was first dis- covered in Washington in 1924 along railroad tracks near Wawawai in southern Whitman Country along the Snake River. It has spread immensely since then, and it is now common in Walla Walla and Columbia Coun- ties.

The only exposure I had to the weed as a kid growing up on a farm between Dayton and Waitsburg in the 1980s was in Steve McLean's agri- culture class. Now, it can be found intermittently along every sidewalk and well- traveled roadway in the area.

Nothing wakes you up in the morning like stepping on a goathead with your bare foot. There is no cheaper conversion kit for changing basketball shoes into golf cleats than walking through a patch. And that is the point of the plant-pardon the pun.

The shape of the goathead serves two purposes. First it acts as a natural defense against predation. Ani- mals that try to eat it, receive wounds to their face and mouth if they're lucky and to their innards if they're not.

The weed is an annual, meaning it only grows from seed dropped by a previous year's plant. The design of the goathead is perfect for spreading seed great distances- even across continents.

The goathead spreads most readily today by being picked up on the soles of someone's shoe, or the pass- ing vehicle tire. It is one of the few weeds spread by air- craft, caught and replanted by airplane tires.

Fortunately, puncture vine, when caught early before fruits begin to form, is easy to control. The key is to be able to identify the plant as a seedling. Puncture vine is generally a creeping, spreading plant with waxy, pinkish-brown vines, and green elliptical leaves-each leaf having a twin precise- ly opposite it on the vine. Plants eventually produce small yellow flowers with five petals, then bunches of five fruits, each with the "chin" of the goathead at the center. Pulling the plants when young is an effective method of control. The plant also responds well to simple herbicides like glyphosate (Round-up) and 2-4D.

The key is to catch them though before heads form, and a mat of puncture vine plants, (like the one on the west side of the old Waits- burg Grange Hall), estab- lishes itself and drops thousands of these seeds.

So please do yourself, and every kid with a bicycle a favor. Control your punc- ture vine!