Description Ranunculus Lingua – Water Buttercup Both suitable for Submerged Oxygenating & Marginal. Lingua grows spear shaped green leaves on long sems.  Flowers are bright yellow and buttercup shaped. Plants will grow submerged or on the pond edge creating a floating mat over the pond. Excellent for fish spawning. Excellent edible vegetation for goldfish. Plant in moist soil or submerged up to 30cm Relatively winter hardy. Plant potted in 13cm pottle.