Bog--or marginal--plants thrive in moist-to-saturated ground and in standing water. Many require less than four hours of daily sunlight, providing options for gardeners in search of plants for shady ponds. Both blooming and foliage varieties are available, in a wide range of heights, forms and colors. Some of the most spectacular pond plants, in fact, are bog plants, according to the University of Illinois Extension.
Sweet Flag "Variegatus"
White-and-green striped, swordlike leaves make sweet flag (Acorus calamus) "Variagatus" an attractive addition to pond edges. The plant's green-flowered, leafless stalk appears in late spring before its berries, according to the Missouri Botanical Garden. Sweet flag "Variagatus" is hardy to USDA zone 4 and tolerates sunny to partially shady locations with consistently wet soils or up to 9 inches of standing water. Given enough time and the right conditions, it will form large colonies.
American lotus (Nelumba lutea) is native to calm, freshwater locations including sloughs and oxbow lakes across the Eastern United States. With 2-foot-wide, flat blue-green leaves that float on the water's surface, this is among the showiest of bog plants. In June and July, its 3- to 6-foot stalks bear fragrant, cuplike blooms. Spreading up to a foot across, the pale yellow flowers have deep or yellow stamens surrounding inverted, yellow pistil-holding cones.
Lasting 48 to 72 hours, the flowers close each night. Eventually fading to brown and hardening, their cones drop into the water and disperse seeds, according to the Missouri Botanical Garden. American lotus requires a sunny location in quiet water and wet, fertile loam. Each plant will spread up to 4 feet from a pond's edge.
Grassy arrowhead (Sagittaria graminea) is a long-blooming bog plant of the Central United States' ponds, sloughs and swamps. Hardy to zone 4, it stands up to 2 feet high. Its narrow, lance-shaped, green leaves and flower stalks rise separately from a central clump. From late spring to early fall, arrowhead's upright stems have white or pink-tinged, three-petaled blooms. The plant will grow directly on the shore or submerged up to 1 foot deep, according to the Missouri Botanical Garden. It prefers calm water and full sun--for maximum flowering--to partial shade.
Few bog plants can compete with cardinal flower (Lobelia cardinalis) in terms of color. This tough, bellflower family perennial has upright, 2- to 4-foot stems with lancelike green foliage. Between July and September, their spikes of brilliant red--occasionally white or pink--tubular blooms will have butterflies and hummingbirds flocking to the water's edge, according to the Missouri Botanical Garden. Growing wild along streams, swamps and sloughs, cardinal flower needs constantly moist to wet, fertile humus-rich soil and sun to partial shade.