Plans are nearly complete for a wetlands reserve restoration that will replace trash and weeds with native plants and a public trail in a highly visible spot at the Carlsbad-Oceanside border. The vacant land along South Coast Highway is opposite the Buena Vista Audubon Society’s Nature Center. The nonprofit purchased 3.5 acres of the roughly 6-acre site in 2016 for $1.55 million raised in donations, nearly a decade after a developer’s proposal to build a multi-story, 82-room hotel there failed. Much of the site is covered by ice plant and invasive, non-native weeds. It’s also littered with trash, much of it left by people who sometimes camp hidden in the brush. Most of the land is in Oceanside, but a fraction is in Carlsbad and owned by the state Department of Fish and Wildlife. That’s because Carlsbad’s boundary includes all of the more than 200-acre Buena Vista Lagoon, and the state owns the lagoon.