Saturday, August 21, 2010

The Vulcan bike path will destroy your tires

These are goat head thorns:

Whether you call it goat head, stickers, puncture vine, or sand bur, this plant is about the most obnoxious weed on the planet. It produces tiny goat head shaped burs that poke the foot and flatten bicycle tires. A large patch of them can even flatten the tires on a small car.

Puncture Vine is an invasive species of plant that originally came from Europe. The botanical name is Tribulus terrestris. This fast growing annual sends out a low forming, dense mat of tiny leaflets. The stems can grow up to 6 feet in length, covering large areas in a matter of a couple of months. They bloom in the early summer, producing tiny 5 petaled yellow flowers. The fruit of the puncture vine looks like a spiny 5 sided Maltese cross. After the individual fruit bursts open, it releases the goat head thorns.

The bike paths along the east side of 101 and west side of Vulcan between Encinitas and Leucadia Boulevards are absolutely infested with them. The photo above was after a very short jog along the path.

Goat heads will go straight through bike tires and give you multiple punctures. Tony Kranz hit them a couple weeks ago, and more recently an entire family's tires were massacred out on the same paths.

The city needs to remove this invasive, non-native species ASAP.


  1. I'm thinking of starting an online petition to get the city to eradicate the Puncture Vines. Does anyone else have a similar plan? Morgan.

  2. It's damn near impossible to eradicate them. They've spread over much of the United States, and because the seeds stick to shoes and tires, they're readily transported from one place to another. The plant can be locally controlled by planting competitive desirable plants, as in well-kept lawns. It may be possible to beat them back along jogging paths and bicycle paths by spraying herbicides such as glyphosate (Roundup) in the spring, before the plants have a chance to produce seeds, but it may take years to get rid of them, since the seeds of this weed remain viable from 3 to 7 years. For your town to control goat head weeds will take a long-term commitment and persistence by the public works or parks and recreation departments, or some kind of community volunteer action.

    In the meantime, the best thing one can do for bicycles is to equip the tires with tire liners, tough vinyl strips that one puts between the tire casing and the tube. It should be possible to retrofit a bicycle for $10 to $15. The slight expense is well worth it compared to the aggravation of repeated flats and having to push one's bicycle back home or to one's car, which could be several miles away. I retrofitted the tires on two bicycles over 8 years ago, and neither bicycle has suffered a flat from goat head thorns, glass, or metal since then.