Tom Keeney describes the appearance and detrimental effects of pepperweed during an inspection of the San Luis Rey riverbed.

From their vantage point, Keeney, Gail Campos, Tiffany Kayama and Melanie Stalder could see workers from Recon Environmental, Inc. in the riverbed spraying to eliminate patches of pepperweed.

The exotic, according to Keeney, had been in the area all along, but its growth was inhibited by the arundo. When the Corps removed the arundo, it provided an opportunity for the pepperweed to thrive.

In late 2007, the U.S. Army Corps of Engineers began removing arundo and other exotic plants from the San Luis Rey River. The work was part of an effort to allow infrequent but potentially dangerous floodwaters to flow from Lake Henshaw through open, business and residential areas to Oceanside, Calif. and into the Pacific Ocean. That plant removal stopped in April when environmental restrictions put a halt to work in areas where the least Bell’s vireo, a federally-protected bird, nests.

Tom Keeney (center) and (from Keeney, L to R) Tiffany Kayama, Melanie Stalder and Gail Campos meet with representatives from Recon Environmental, Inc. to determine areas to be inspected for pepperweed.

"This is a good demonstration of how we can address issues like this when the agencies work together," Keeney said.

Walking among the thick brush, Keeney pointed out areas where pepperweed had taken hold. The invasive shrub develops roots up to 30 feet deep. The trick is to spray it before it has gone to seed.

"As long as it’s got flowers," Keeney said, "the seeds haven’t developed. We’re here at the right time."

Keeney stressed the importance of Corps and other biologists working actively in the field. "Nothing takes the place of being out here and seeing it, being in it," he said.