Ranunculus ficaria ‘Flore Pleno’ – A tuberous perennial often used as an ephemeral groundcover in part shade exposures with moist soils. It bears double yellow lowers (with greenish centers as they open) from April to May. The glossy green leaves resemble Marsh Marigold and form a dense mat. It is not as invasive as the species. Grows 4″ high by 12″+ wide. Zone 4.