Ever drive along the roadways of California and notice a huge, fountainy grass with big, feathery, buff-colored plumes?  To the untrained eye, pampas grass (Cortaderia selloana)  looks like a statuesque, beautiful grass, but oh!  Beware!

Pampas spreads out of control

Pampas spreads out of control

In her wonderful horticultural history, Southern California Gardens, Victoria Padilla tells how in the mid 1800s, Joseph Sexton “the father of horticulture in Santa Barbara” popularized pampas.
Vast acreage was devoted to pampas as demand grew, not just for  garden plants but also for plumes to decorate hats and other items.  “Pampas grass became so popular.” Padilla writes, “that it was almost a national emblem, and was used not only for indoor decorations, but for parades and even on holiday greeting cards”

Notice how the pampas towers over John Sexton!

Notice how the pampas towers over John Sexton!

If only Sexton had known what would happen not a full century later.  Pampas was so well adapted to growing in California’s Mediterranean climate, this South American native has become one of our worst invasive plants.   It invades natural habitats, crowding out the plants that native animals depend on for food, shelter, and cover.  It clogs waterways causing the buildup of sediments and again destroying native habitats.  Its dry leaves and plumes allows fire to jump from plant to plant, even across wetlands.

Pampas’ destructive nature has not gone unnoticed.  There are efforts at every level in the state to stop the sale of pampas in nurseries.  At the same time, millions of dollars are spent annually in eradication programs both for habitats and for garden situations.

In fact, home gardener Sandy Shapiro initiated a backyard pampas eradication program in his hometown of Encinitas, California.  Project RIP, or “Remove Invasive Pampas Grass” was intended as a model program to show residents how to get pampas off their properties.

Still, wholesale and retail growers continue to offer dwarf and variegated hybrid pampas such as such as ‘Gold Band,’ ‘Silver Comet,’ and others.    Because identical looking seedlings don’t pop up in the nurseries, they assume these plants are sterile and “safe” for garden use.   But are they right?

Pampas is beautiful, but beware!

Pampas is beautiful, but beware!

Not according to Marie Jasieniuk, Assistant Professor in the Department of Plant Sciences at UC Davis. Jasieniuk identified genes found in both wild (invasive) pampas populations and cultivated landscape pampas varieties sold by nurseries and garden centers in California, in other states across America, in Europe and New Zealand.  She compared the genetics of cultivated varieties to 29 wild populations of pampas from Crescent City in the north to La Jolla in Southern California.

Jasieniuk’s research determined that wild populations of pampas have genes in common with the so-called sterile, cultivated varieties.

In other words, while they don’t breed true-type offspring, cultivated pampas definitely breed with the wild growing pampas and contribute to the overall problem of invasive pampas.

According to Jasieniuk, ” landscape plantings are probable sources of invasive populations…  Our results strongly suggest that …. landscape planting has contributed to the range expansion of invasive C. selloana in California.”

Further, results suggest that even as we spend millions of dollars eradicating wild growing populations of pampas, landscape plantings continue to “replenish” the wild populations. Therefore, Jasieniuk writes, “management efforts that target secondary releases by eradicating landscape plantings may be highly effective in controlling existing invasive populations as well as preventing further invasive spread.

In other words, to eliminate invasive pampas from both native habitats and cultivated areas, we need to stop planting all varieties of the pampas, Cortaderia selloana in our gardens.

Beautiful but dangerous.  Sounds like the beginning of a good novel.  If only it were fantasy rather than reality….

9 Comments

  1. max on February 9, 2010 at 10:46 pm

    I don’t even think it’s beautiful. RIP indeed!

    Is that an Agave in your sidebar?



  2. Charles E. Dills on February 10, 2010 at 8:58 am

    When I first moved to San Luis Obispo, I bought a house in what is known as the Laguna Lake area. I had seen Pampas Grass and thought it looked attractive so I bought three plants and planted them in a row at one corner of the house, kind of separating the side yard from the back yard.
    They grew and became adult plants. After a couple years I noticed little plants were popping up in my “flower beds” and wondered if they were spreading to the neighbors. I quickly decided they had to go. I tried to dig them out and realized it was going to be impossible for me to do. I think I advertised for help. A tall rangy, old (70) man answered. He had the biggest hands I’ve ever seen. I gave me a bid for the removal. He said he didn’t work by the hour because he wanted to be able to sit down for a bit when he got tired. His bid was very attractive so I told him to go ahead.
    He backed into the plant and started swinging a large adze. He worked his way around the plant and it finally broke loose and he threw it into his truck. He went after the other two and, Voila, they were soon gone. I had several large piles of weeds, trying to clean up the yard so I could start a lawn. He took them out too, using a very large tarp which he would drag to his truck.
    In a surprisingly short time, he cleaned my yard, accepted my check and left.
    They just don’t make workers like him any more! —Chas—



  3. Pete di Girolamo on February 10, 2010 at 4:56 pm

    perhaps the most painful and destructive examples of pampas ‘infestation’ are seen on the ever-sliding hillsides along Highway 1 near Big Sur on the central coast.



  4. Jean Kaiwi on March 7, 2010 at 12:01 pm

    I live in the foothills east of San Diego. When the Mcmansion project went in up above us there was fairly undisturbed chaparral growing. This housing project was required to leave areas undeveloped and posted, “No disturbance beyond this point” signs. Pampas grass, pepper trees, eucalyptus trees, palm trees and many invasive species are used in the landscaping and are escaping into the “protected” areas. I feel frustrated and sad when I walk these areas.

    I see no awareness or responsibility in understanding our native surroundings. No regulations, no education, no protection for what is left of our plant communities within our housing borders. I am looking into buying a large supply of brochures that the Invasive Plant Species Council has and distributing them door to door.

    If you ever fly into either SF airport or Oakland, the landscape is totally pampas and non-native trees.



    • Nan on March 14, 2010 at 10:01 pm

      Hi Jean Thanks for your comment. What you describe is unfortunately common in San Diego, in fact in all of California. It is a very fine line between plants from other parts of the world that adapt and grow well here and those that do so well, that they escape into habitat areas and crowd out the natives.
      I was driving in Malibu recently and saw brooms (Genista/Cytisus), growing amid the chaparral. Anyone from the northern part of the state can tell you how much of a problem it has become there.
      Now, it is marching down south and into our area. I’ve seen it on freeway cuts along Highway 15 as well. And wouldn’t you know it, the big box stores sell it proudly!
      Here in Encinitas, I sit on a city committee that has been working on an invasive plant ordinance for most of the last 2 years. Will our City Council accept our recommendations? Stay tuned!
      And in the meantime, the California Invasive Plant Council website is the best place to look up plants to see if they are invasive in your area: http://cal-ipc.org/
      By the way, the California Invasive Plant Council breaks the California floristic province  into about ten different geographical regions. (State lines are political lines that plants ignore, so various plants that we regard as California natives are also found in Arizona, Baja, Nevada, etc.) When you look at the plants on the invasives list, notice that some might be invasive in your region while others are invasive elsewhere in the state, but not where you live. 



  5. Castles on August 22, 2011 at 2:22 pm

    We are so desperate to get our house that we really loved but failed many times. We got tired of waiting and just settled for the one that we never liked. The old owners planted pampass grass near the garage door almost 7feet tall and 7ft wide. Am almost done getting rid of it and a lot of insects,mice and black widows came out like crazy!! Now our problem is the whole driveway near the fence.It’s about over 20ft wide and almost 5ft tall. We are afraid if there are already snakes in there since it’s next to a vacant lot. Need really badly RIP’s contact number and info. I live in Victorville Ca and you’ll absolutely go crazy with all these pampass grass all over the place. Just google map the address 14976 LUna Rd Victorville and you’ll know what am talking about. Help please. Anyone?



    • Nan on August 22, 2011 at 2:39 pm

      Oh my gosh, that’s terrible! But its a great example of what NOT to do. The best approach now, is to do exactly what you are doing. Take it one clump at a time and arm yourself with long sleeves, long pants, gloves and goggles. Beware the knife-sharp edges of the pampas blades (which you are probably very familiar with by now). Be sure to cut down all flower plumes the moment they appear. Those make the seeds that fly around and germinate all over the place. Its not a fun project but the only other option is to use herbicide which poses another whole dilemma. Wish I had a better answer for you!



  6. Kansas Shawn on February 4, 2012 at 1:33 pm

    I’m amazed after reading this blog! I had NO idea Pampas was so invasive. I’ll be helping my mother this Spring clean up her yard, rebuild the patio and do some new planting. After 20 years of neglect, we’re in for quite a project. We both love the look of Pampas, and that it appears to give you a lot “bang for your buck”. But after reading these comments, it appears that you get more BANG than anything… which we don’t need. We also had never considered the possibility that creepy-crawlies would flourish within the Pampas. Does anyone have a suggestion for something that would be a good alternative? She likes fast growing perennials, color, flowers and drama. But most important, it has to be as maintenance free as possible.



    • Nan on February 4, 2012 at 1:50 pm

      Glad to enlighten you, Shawn. Love the “bang” rather than “buck” analogy! I can make recommendations for alternatives if you can tell me where your mother’s garden is located.