Stinknet, a.k.a. Globe Chamomile.

An insidious weed called stinknet has been spreading throughout Arizona and Southern California for the past few decades. Hailing from South Africa, this weed seems harmless with its small round yellow blooms, but the problems it causes can be devastating. It has been in Arizona since the early 1990s and has increased slowly under the radar for years. It gets its name from the noxious smell it gives off. 

Stinknet has spread throughout the North Valley from the I-17 east to Cave Creek and Carefree between 2005 and 2019. In general, it has trouble competing with native plants, preferring to fill in the empty areas.

However, it is able to sneakily overtake native plants. John Scheuring, conservation director of the Arizona Native Plant Society, said stinknet grows at the base of creosote bushes and tall grass. Over time, it expands and takes over the blank areas. Scheuring said that stinknet’s infestation has exploded over the years as a result of Arizona residents choosing not to remove it because of its attractive yellow flowers.

The infestation has also become rampant partly because the plant wasn’t added to Arizona’s invasive plant list until January 2020. City of Phoenix Park Ranger Brian Miller said that stinknet is sprouting in the cracks of unused sidewalks. He also said that it’s crowding out other invasive plants and has taken over Phoenix earlier than most biologists thought it would. 

Both Scheuring and Miller say that the stinknet infestation is also a major concern for one main reason: fire.

Scheuring said that stinknet burns fast like gasoline. It’s like kindling and can cause fires to spread over acres very quickly. Many wildfires have involved stinknet – including Cave Creek’s 980-acre Ocotillo Fire in May. Scheuring also said that any stinknet seeds already in the soil when a fire comes through will come up the next year because the plant thrives on disturbed soil. 

The primary way to get rid of stinknet is herbicides. However, residents can grub (the removal of roots) it out before it blooms (February-April). There aren’t any preventative measures to keep it from growing in a yard because the seeds are tiny, and just one yellow bulb can drop up to four hundred seeds.

“It is something worth taking the time to pull and take out because it promotes fire. If you do grub it out, you are preventing fire, especially around your property,” Miller said. “As a land manager, it’s frustrating to see it suddenly appear on the invasive plant list. But it’s here now, and it’s prevalent, and it’s not going to go away. It’s going to be part of the urban area like the tumbleweed.”

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