Certain flowering plants are adaptable for underwater use. These flowers consist of plants that prefer full sun exposure with the capability of thriving while submerged with approximately 4 to over 10 inches of water above the crown of the plant. Underwater flowers often provide shade to fish and add interest to a water garden.
Yellow pond-lily (Nuphar lutea) is a flower suitable for underwater growth. These are perennial flowers that display "cup-shaped yellow-green" flowers and thick leaves resembling the shape of a heart, according to the USDA NRCS National Plant Data Center. Bloom time is May through October when blossoms open during the morning hours and close at night. These underwater flowers grow to a height of 6 to 24 inches and thrive at a depth of 1 to 3 feet of water. Though they prefer full sun, yellow pond-lilies tolerate partial shade. Plant in USDA Hardiness Zones 4 to 10.
Golden club (Orontium aquaticum) is an erect, clumping underwater flower that displays white and gold blooms and green foliage. These plants tolerate partial shade. Growing to a height of 1 to 2 feet, submerge golden clubs to a depth of up to 10 inches for successful growth. Bloom time is April through May. Plant golden clubs in USDA Hardiness Zone 6, according to the Maryland Sea Grant Outreach & Extension.
Waterlilies (Nymphaea species) are well-known underwater flowers that display round, spiked blooms in whites, yellows, pinks and purples with vivid green foliage. These clumping plants bloom from May to September and can be submerged to a depth of 18 to 24 inches, according to the Maryland Sea Grant Outreach & Extension. Growing to a height of 6 inches, waterlilies are a food source for wildlife like birds. Plant waterlilies in USDA Hardiness Zone 3.
Water cannas (Thalia dealbata) are underwater flowers that display spiked, vivid purple flowers with large, glossy green leaves, according to the Maryland Sea Grant Outreach & Extension. These clumping plants bloom from July through September and may be submerged to a depth of up to 12 inches. With a height of 6 to 8 feet, these flowers often protrude far beyond the surface of the water. Plant in USDA Hardiness Zone 7.