Effort to fight invasive plants in California targets nurseries
The delicate, knee-high grass Nassella tenuissima rises like a pale yellow cloud, with wispy tassels spilling from needle-thin green stems. Mass-planted, the grass evokes a rippling golden sea.
“If only those plants weren’t so beautiful,” Jan Merryweather says, sighing. “People get love-struck.”
Nassella tenuissima, or Mexican feather grass, as it is more commonly known, is enemy No. 1 on the hit list of PlantRight, a campaign through the nonprofit San Francisco-based group Sustainable Conservation that aims to rid the state of invasive ornamental plants. Merryweather, PlantRight’s senior program manager, is on a very specific mission: to shut down the retail sales of plants damaging to the California ecosystem, the popular Nasella tenuissima first among them.
PlantRight says invasive plant species are the second-greatest threat to biodiversity in California and the world, after human development. “Invasive plants are like champion Olympians — higher, faster, stronger,” Merryweather says. “They are the first to get to the sun, their seed production is prolific and they often replace the natural forage for our native animals and insects. Some clog waterways; some can even alter soil composition.”
About half of all invasives come through the nursery supply chain, and that is PlantRight’s target. Rather than taking an antagonistic approach, however, the group looks to join with nurseries and the growers to come to a mutually agreeable method of removing these plants from the marketplace. Since the program’s creation in 2006, PlantRight has helped reduce the sale of California’s most damaging invaders by 70%.
A recent PlantRight campaign sought to raise $28,000 to buy out from a cooperative grower, at cost, 14,000 Mexican feather grass plants. PlantRight raised $23,000, and more money through private groups may be coming in.
Two other plants on the Southern California watch list include green fountain grass (Pennisetum setaceum) and periwinkle (Vinca major). All are considered “emerging invasives,” tagged by a new plant-risk evaluation tool used at UC Davis Center for Urban Horticulture that predicts how a plant will behave. Mexican feather grass, with its 70,000 seeds per plant, “shows high risk,” Merryweather says. “Left unchecked, we have all the confidence in the world it will become the next pampas grass” — shorthand for a highly combustible, inedible, widespread problem.
PlantRight’s website spotlights the invasive plants and offers noninvasive, often look-alike alternatives. This type of educational effort, Merryweather says, may help growers produce, and consumers buy, only plants that “make ecological and environmental sense.”