Water lettuce for sale, £1 per plant. Nutrient Filtration: Their long, feathery root systems absorb excess nutrients and nitrates, starving algae. Shade and Cover: Broad floating leaves shade the water, cooling the pond and making fish feel safe from predators. Habitat: The roots provide spawning grounds for fish and a safe nursery for fry. Non edible. For ponds only. Plant size ranges between 2-4 inches. Pick up only. Morley, Leeds, West Yorkshire.