Giant salvinia is an invasive fern, native to Brazil, that is choking the waterways in the Deep South. Photo courtesy Louisiana Department of Wildlife and Fisheries.

Barbara Klingler's moonflower vine produces more than 500 blooms at a time.

Moonflowers open in the evening and twist closed in the morning light.

These dinner-plate-size blooms are stunning on Martha Ferrell's giant hibiscus.