Search-and-Destroy Mission Weeds Out a Growing Threat

Volunteers hike Mission Viejo Land Conservancy hunting a foreign invader, Italian thistle.

By ELAINE GALE, Times Staff Writer

With trowels in hand, a group of volunteers hiked through the Mission Viejo Land Conservancy on Saturday determined to help rid the pristine wild lands of an environmental menace: squat Italian thistle.
"This is the enemy," said conservancy director Laura Cohen, holding up one of the insidious plants for her throng of volunteer weed whackers to examine. The thistle has started to take root in a two-square-mile area within the conservancy, and if left alone, it will squeeze out native plants like prickly pear and coastal sage scrub that provide refuge for endangered birds, butterflies and other animals.
And since a single Italian thistle weed grows quickly in thick clumps, dropping over 1,000 seeds per plant, there was no time to waste.
"Remember, when you pull one, it's like getting rid of a thousand of them," Cohen said.
The thistle sprouts out low to the ground but can grow up to 2 or 3 feet high, said Cohen, who organized the daylong outing that included a Bahai youth group from Laguna Niguel and other environmentally minded folks.
The pernicious weed--which looks innocent enough with its five fuzzy trademark leaves--is less known than the artichoke thistle, another invasive weed that carries huge, knifelike leaves and trailing stems. For more than a decade, artichoke thistle has been listed by the California Exotic Pest Plant Council as one of the 10 most invasive wild land weeds.
But in recent years, Cohen said, the Italian thistle has become more of a concern for environmentalists, largely because it is considerably smaller than its artichoke counterpart yet just as devastating. The Italian thistle has also joined the hit list of the California Exotic Pest Plant Council as one of a dozen "kill on sight" weeds.
And while artichoke thistle can be killed by spraying it directly with herbicide, the method is not a good choice on the low, snaking Italian thistle because the chemicals could also eliminate other nearby native species, like miner's lettuce, Cohen said.
Wearing boots and a sun hat Saturday, Paddy Bagmard, 81, of San Clemente gingerly stepped near the dirt trail to extricate one of the spreading weeds. Remembering that Cohen said the weeds were edible, although not particularly tasty, she plucked a fuzzy leaf and nibbled on it.
"It has a bitter taste, like spinach," Bagmard decided. "But it's not too bad."