Marginal water plants are those who grow at the edge of the pond.

Acorus, sweet flag	Sweet flags are an addition to the water garden for their neat, clean appearance. It will lose its foliage in the winter. All sweet flags tolerate freezing temperatures and can freeze solid provided they remain in the water garden, they may be overwintered by mulching them into the perennial border. The flowers are cone-like and inconspicuous on the smaller forms. All will grow well in sun to shade and require soil that is consistently moist. They are generally easy to grow and pest-free. Smaller forms can be prone to spider mites. There are also many different varieties.
Cyperus, umbrella grass	These are mostly tropical water plants grown for their ornamental sprays of leaf fronds that resemble thin, papery palms. The flowers are really seed heads. The heads of the plants look like parasols. The can come in different variety's colors and shapes. It needs little care other than feeding in the spring and summer, also trimming any brown tips. Situate in sun to part shade in moist soil or water to 6 inches deep or more.
Echinodorus, melon sword	Melon sword is noted for its foliage, which is usually sword shaped, or spoon shaped. Alot of these plants are grown as aquarium plants because of there attractive under water appearance. Water gardeners like them for their out of water look. The flowers are white and bloom in summer, or year round where active growth can take place. They are very easy to grow and require little maintenance, though they quickly outgrow their pots and benefit from repotting every few years. It generally overwinters well in cool regions, but in areas of considerable frost bring the plant indoors to a greenhouse or warm sunny room for the winter. There are many different species of this plant. Which are cool so check them out!
Hydrocotyle, pennywort	These are low growing plants,running aquatics with round, umbrella-like. often toothed leaves that stand up straight from running stems. The leaves are fleshy and usually shiny. This plant will also remain green from spring to fall. These plants will also quickly create shade over the pond. Flowers are inconspicuous , white or sometimes green tufts that often remain under the leaves. Most species grow well in sun to part shade. Cold tolerant species overwinter well in the pond but should not freeze. It is best to move them to the bottom of the pond.
Canna	These are plants your grandma used to grow, only much improved. Tall and impressive, they are topped by extremely colorful flowers that start in midsummer and keep going right until frost. Two kinds of cannas grow well in saturated soil or with water over their crowns. They will grow to varying heights and 2-3 feet wide. All the water cannas bloom throughout the summer. The second kind is the water-tolerant cannas. These are terrestrial forms that adapt to growing in water logged soil but that can also grow in the perennial border. Canna foliage is large, long and tapered, very tropical looking. Hues range from bright green to blue-green, dark purple, or crimson. Some are striped in yellow, white, or red. Plants commonly grow to several feet in height in a single season, forming a large mass of tubers at the base. They are a suitable accent plant in the water garden and make excellent specimens when planted in a container. Lower growing, more creeping water plants, such as pennywort, are good understory complements to the large, bold effect of canna. Flowers also come in a wide variety of colors, from delicate creams and yellows to brassy oranges and reds. Full sun is best for bringing out the strongest color and most flowers, but cannas will grow in pretty deep shade. Propagate from seed or by division of the tubers. Seed is a useful method only for the species, since seed grown varieties may not be true to the parent. Stick to division for most cultivator. Cannas are rated hardy in Zones 8b-11. The generally accepted view is that cannas are tropical plants that cannot withstand a winter freeze. For this reason it is usually recommended that they be brought indoors for the winter. They Can also be left to dry out, so the tubers can be cleaned and stored for the winter. Cannas may be affected by aphids or Japanese beetles during the summer. If brought indoor for winter they may also be prone to spider mites. Canna rust may also occur among plants tat are not kept very wet or are not cleaned well in the fall before being put away for the winter.