Marginal water plants are good for the borders and edges of a bog or water garden. Plants that can grow in very wet ground or some standing water are classified as marginal plants. Bog gardens are typical uses for any plant classified as a marginal water plant, but some are going to be able to live in fully submerged water gardens.
Japanese Sweet Flag
Acorus gramineus, the Japanese sweet flag, has 6- to 14-inch grass-like leaves. Horn-shaped tiny flowers appear in summer. The plant only flowers in water. Plant a Japanese sweet flag in full sun to partial shade in very moist soil or wetland areas as a marginal plant. Propagate via spring rhizome division. Uses include a groundcover for the margins of a bog garden; it releases a cinnamon-like smell when stepped on.
Typha latifolia, the cattail, is a perennial. It has sword-like leaves 3 to 9 feet tall. Flowers are brown and cylindrical, looking like cat’s tails. It is typically used as a marginal plant around lakes and ponds. Plant a cattail in full sun in water under 16 inches deep. Propagate via division of root stocks.
Zantedeschia aethiopica, the calla lily, is a perennial. It gets 2 feet tall with large leaves and various colored flowers. Leaves look like those of a banana plant and give a tropical feel. They flower spring and again in fall. Plant a calla lily in rich organic soil with full sun or light shade. Calla lilies prefer moist soil and shallow water. Propagate via clump division. Sap can irritate skin, and all parts of this plant are poisonous; take care around pets and children.
Cyperus papyrus, the papyrus, is a fast-growing evergreen perennial. Leaves wrap the bottom of stems 10 feet tall with large clumps. Spikes are 5 to 12 inches long. Flowers are on top, but are tiny. Plant a papyrus in shallow water in sun or partial shade. It is good for bog gardens. Propagate via clump division.
Equisetum hyemale, the horsetail, is an evergreen perennial. It will get 3 feet tall with evergreen stems under an inch wide. Leaves are small and around the stem. There are no seeds and no flowers on a horsetail. A cone-shaped strobilus houses the spores. Plant a horsetail in full to filtered sun with very wet soils. Propagate via clump division. It is good for the edges of ponds.