Debbie Arrington

Seeds: PlantRight tries to stop escaped thugs

As a rampant reseeder, Mexican feather grass (Stipa tenuissima) is an invasive plant in California and on the PlantRight list of poor choices for gardens.
As a rampant reseeder, Mexican feather grass (Stipa tenuissima) is an invasive plant in California and on the PlantRight list of poor choices for gardens. Monterey Bay Nursery Co.

They’re usually gorgeous; that’s the start of the problem. They grow easily and often freely, propagating offspring effortlessly. With a little water and time, they really do take over.

And that’s when a beautiful ornamental plant becomes an invasive thug.

A statewide campaign is trying to corral those destructive plants and keep them out of nurseries before they have a chance to spread any further. Called PlantRight, the program has found major allies in The Home Depot as well as local nurseries such as the Sacramento-based Green Acres Nursery & Supply.

This spring, more than 200 Home Depot stores in California agreed to phase out invasive species pinpointed by PlantRight’s experts. That list includes such popular landscape plants as Mexican feather grass and Chinese tallow tree.

“Partnering with PlantRight in California is the right thing to do for our communities,” said Brian Parker, The Home Depot’s senior nursery buyer. “We’re committed to providing the best plant options for California, including drought-tolerant and non-invasive varieties.”

Some of the most invasive (and drought-tolerant) plants in California started in private gardens. They were bought at nurseries and added to home landscapes. Then they escaped into the wild.

That’s where the same attributes that made them such easy-to-grow garden wonders turn them into environmental monsters, suffocating native competition and wiping out pristine wilderness. It’s expensive, too. California annually spends more than $82 million to control invasive plants.

Jan Merryweather remembers her personal epiphany.

“I was in love with glowing golden hills of broom,” recalled Merryweather, senior project manager for PlantRight. “We all grew up thinking it was a wildflower. It was so pretty and it was everywhere. It was deceptively beautiful; it was destroying the real wilderness.”

Brooms – starting with Scotch and joined by French, Spanish, Striated and Bridal Veil – are tough members of the pea family. Gold Rush-era nurseries first popularized Scotch broom in the 1850s as a perfect drought-resistant ornamental plant for California gardens. In the early 1900s, landscapers planted Scotch broom along highways to control erosion. It wasn’t until the 1930s that state authorities realized broom was a little too hardy.

How tough is broom to eliminate? Fire can’t kill it; wildfire actually renews the plant’s growth and makes it stronger. Broom can turn the soil toxic to other plants and thick stands crowd out any competition. Amazingly prolific, each broom plant can produce up to 12,000 seeds.

Now, Scotch broom covers an estimated 700,000 acres of California open space – roughly the size of Yosemite National Park.

In the Bay Area, French broom is spreading at the rate of 50 more acres a year despite thousands of volunteer hours to eliminate plants. It already occupies more than 1,400 acres in Marin County.

One Scotch broom plant can produce 12,000 seeds.

“Invasive plants are just like littering,” Merryweather added, “except it’s biological litter and it reproduces quickly.”

Since 2006, PlantRight experts have been surveying California retail nurseries to see if they offer plants that have been determined to be invasive.

“We had 19 plants on our original list,” Merryweather said. “In 2006, every retail nursery carried at least one of these invasives. Now, we’re down to 30 percent.”

As growers phase out these thugs, PlantRight revises its list, which is now down to 10 plants.

“Some are no longer an issue, but other plants are emerging as invasives,” Merryweather said. “An example is Mexican feather grass. It was introduced as an alternative to pampas grass. People fell in love with Mexican feather grass. It was gorgeous. But it also makes a ton of seed; you see it literally running down the street, sprouting everywhere. It’s become invasive enemy No. 1. But according to our 2014 survey, 38 percent of nurseries still carried Mexican feather grass.”

Other suburban plants such as highway iceplant and vinca seem innocuous, too. But that’s the problem; they really are everywhere now.

The Home Depot’s commitment is huge because of sheer numbers, Merryweather noted. About 70 percent of annual plant sales come from big-box stores.

Stopping invasive plants starts with awareness, both for retailers and the public.

“PlantRight makes it easy for the industry to do the right thing – voluntarily,” said Green Acres’ Ashley Gill, who also is a board member of the California Association of Nurseries and Garden Centers, the state’s nursery trade group. “First and foremost, PlantRight really listened to the industry’s needs and concerns in developing an effective solution. They also knew blanket regulation, which can have unintended downsides for businesses and might still not end up fixing the problem, wasn’t the way. And they used sound science to inform all decisions, which boosted the industry’s trust and desire to help.”

PlantRight’s motto is simple: “Don’t grow crazy.” Instead of invasive plants, go for less-aggressive alternatives.

Instead of Mexican feather grass, try blue grama grass or Mexican deer grass for the same feathery look with less seed and better manners.

“It’s a way for gardeners to feel good and do their part,” Merryweather said. “We’re hoping that with The Home Depot participating, that pumps up this conversation and growers and gardeners can see they’re part of the solution.”

PlantRight enemies list

PlantRight, the statewide campaign to phase out invasive ornamental plants, identified these 10 plants as the highest priority to eliminate from retail nurseries:

  • Mexican feather grass (Stipa tenuissima)
  • Green fountain grass (Pennisetum setaceum)
  • Pampas grass (Cortaderia selloana)
  • Water hyacinth (Eichhornia crassipes)
  • Yellow water iris (Iris pseudacorus)
  • Highway iceplant (Carpobrotus edulis)
  • Big leaf periwinkle (Vinca major)
  • French broom (Genista monspessulana)
  • Scotch broom (Cytisus scoparius)
  • Chinese tallow tree (Triadica sebifera)

Find out more, including alternatives, at www.plantright.org.

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