Bulltongue arrowhead (Sagittaria lancifolia) is a great pond plant and long-blooming.. Members of the Water-Plantain Family grow in water, in swamps, on muddy banks, or occasionally in wet sand. Good for water gardens. They should be planted no deeper that 12″ in a water garden in a full sun location. They spread easily by rhizomes and may be thinned if you have limited space. Set up a pond or a water collection tank near a downspout to supplement water.