Globe Chamomile: A flower, or a beautiful beast taking over the Sonoran Desert Foothills?

By TARA ALATORRE

Pictured: Globe Chamomile that has taken over a private lot along New River Road. Photo by Karen Alexander
Pictured: Globe Chamomile that has taken over a private lot along New River Road. Photo by Karen Alexander

CAVE CREEK –Spring has officially arrived, and if you have looked outside you can’t help but notice the abundance of bright, yellow, globe-shaped flowers blanketing every square-inch of the desert, especially in the northern, rural parts of Maricopa County.

The flower that has literally taken over yards, parks, highways, medians, open desert, cracks in the sidewalks and any other sunny crevice of disturbed soil it can lay root into is called Globe Chamomile or Oncosiphon piluliferum. It is also commonly referred to as Stinknet due to its strong, vile odor that emanates from the lacey looking leaves, and unfortunately its smell isn’t the only awful thing about it. 

Pictured: A property on top of Black Mountain in the Desert Hills area where landscaping company Jamiesons Greens manually removed the Stinknet. But below the property line remains swaths of the invasive plant. Photo by Jamie Schmitt
Pictured: A property on top of Black Mountain in the Desert Hills area where landscaping company Jamiesons Greens manually removed the Stinknet. But below the property line remains swaths of the invasive plant. Photo by Jamie Schmitt

Stinknet is considered a prolific, fast moving invasive plant by Maricopa County and it has heavily infested the Sonoran Desert Foothills area. The bulbous flower has dominated the landscape outcompeting native plants in the open desert, causing people to have allergic reactions from its leaves and abundant pollen and it is resistant to most commercial herbicides.

Stinknet was first noticed in the Spur Cross Conservation Area in 2005, by 2008 the plant had become profuse. It  spread from initial infestations in North and Northwest Phoenix into the metropolitan area and is now spreading to Southern Arizona, according to Maricopa County Parks Ranger Kevin Smith.

“A lot of people don’t realize it is not native so they don’t pull it because they think it is pretty,” Ranger Smith said, while he stands surrounded by Stinknet as far as the eye can see in the Spur Cross. “I don’t think the problem is going away.”

The plant was first identified in Maricopa County in the 1990s, by 2005 it had proliferated along the Interstate-17 near the Ben Avery Shooting Facility, Cave Creek, New River and parts of the Tonto National Forest, according The Arizona Native Plant Society (ANPS).

A close-up look at the stems and flowers of Globe Chamomile or Stinknet, which is an invasive weed and the Sonoran Desert Foothills has become the epicenter of the invasion. Photo by Tara Alatorre/Staff
A close-up look at the stems and flowers of Globe Chamomile or Stinknet, which is an invasive weed and the Sonoran Desert Foothills has become the epicenter of the invasion. Photo by Tara Alatorre/Staff

“The infestation of the Ben Avery Facility provided a perfect storm for infestation in Maricopa County.  It was allowed to bulk up unimpeded for over 15 years,” Arizona Native Plant Society Conservation Committee Chairman John Scheuring stated in a PowerPoint he presented to the Desert Botanical Garden in Phoenix this January.

The plant sprouts around late November, flower beginning in January, then quickly go to seed by early February going through up to three generations from November to April.  In wet years, seed dispersion can continue into late May, experts say.

“If infestations are allowed to propagate over the course of several seasons, they will form dense stands with prolific seed production,” stated Maricopa County Parks and Recreation Department in a brochure it released about Stinknet.

Pictured: Globe Chamomile that has taken over an area of open desert in the Cave Creek area. Photo by Jamie Schmitt
Pictured: Globe Chamomile that has taken over an area of open desert in the Cave Creek area. Photo by Jamie Schmitt

The prodigious plant and seed production combined with how easily the lightweight seeds can be spread by wind and vehicle traffic makes the Phoenix Valley rife for globe chamomile infestation, according to ANPS.

This year’s winter rains caused a superbloom, and the Stinknet was no exception, causing major infestations all over the North Valley, according to Jamie Schmitt, the owner of the local landscaping company, Jamieson Greens.

Schmitt says the other major problem in the battle against Stinknet is that typical herbicides don’t work – Glyphosate is not match for this flowering foe.

“Roundup does not work! You can spray it on the plant and everything around it will be dead and the Globe Chamomile is just fine.” Schmitt said. 

The landscaping company has a client that lives on top of Black Mountain in the Desert Hills area and Schmitt says the entire hill “is just infected.” So he and his crews spent the whole day mowing the Globe Chamomile down on the property in an attempt to stop its propagation. 

However below the property line is still a blanket of yellow, stinky flowers.

“You can’t not see it,” he said. “It’s just crazy.”

Scmitt’s advice to the residents that did not pull up the Globe Chamomile before it flowered and are now battling the Stinknet assault is to mow down or trim the plants, removing the flowers and its seeds. 

Other removal methods that are recommended by Maricopa County are using the herbicides Trichlopyr or Garlon, or using Glyphosate with a surfactant like Hasten.

“I know it sounds horrible, but the best way to get rid of it is physical labor,” Schmitt said. “And try to get at it before it has flowered.”

For more information about Jamiesons Greens and its services visit: jamiesonsgreens.com, email jamielee@JamiesonsGreens.com or visit their Facebook page.  For more information about  AZNPS visit AZNPS.com.