Wetlands, defined as areas of land where the water level remains near or above the surface of the ground for the greater part of the year, are common in much of the temperate and tropical zones. In the wild, such areas are classed as bogs, fens, marshes and swamps, depending on the content of the soil and the plants that grow there. Swamps, for instances, have more trees and shrubs, while marshes have more grasses and reeds. In this article we shall discuss wetlands as a form of landscaping, and more specifically how one type of plant may be used for the purpose.
The water willow, an evergreen perennial of the genus Justicia, is native to warm temperate and tropical areas of the New World. There are at least 76 species, of which the American (Justicia americana) is the hardiest, able to grow as far north as southern Alaska. It grows partially submerged from creeping rhizomes (thick plants that grow underground, from which shoots and roots grow).
Justicia americana is a small plant, reaching heights of no more than 3'4". Its violet and white flowers come out early in the summer and bloom until autumn is well under way. It prefers to grow in shallow water or on the banks of lakes and ponds where the soil is either rocky or sandy, forming colonies in those areas.
Cultivating the tree
The water willow requires soil that is high in moisture and full exposure to the sun. The rhizomes can be transplanted into water that is less than a foot deep.
Because these plants propagate from both seeds and roots they are rather difficult to control, although a number of compounds, particularly Weedar 64 and the fluoridone compounds Avast, Sonar and Whitecap, have proven to be effective at keeping their numbers down. Goats, too, may sometimes forage on the emerging growth. Chemicals should be used with care as they tend to disrupt the ecosystem by killing off many of the fish who live in the water. It is therefore important to check all package labels for restrictions on use.