Water Hyacinth Pontederia crassipes

Water hyacinth is listed as an illegal plant in South Carolina and on several federal registries.

Water hyacinth is a vigorous, herbaceous perennial or annual, floating water plant in the pickerelweed family with showy purple flowers and long, feathery, dangling roots. In a temperate climate, flowers bloom from mid-summer to mid-autumn; in tropical climates, blooms appear throughout the year. The flowers are diurnal, open in the morning and withering by evening. The plant is often found on the quiet water of the margins of ponds. In tropical climates, the plant is perennial, but in cooler climates, it is an annual that dies back in winter. The genus name honors Guilio Pontedera, an eighteenth century professor of botany at Padua.

Water hyacinth requires abundant sunlight for full flowering and thrives in warm temperatures. To grow, you can plant roots in spring into the mud at the edge of a pond. Keep in mind that the plant does spread aggressively by means of rhizomes and it may be best to grow the plant in a container containing organic soil, placing the container under 3 to 5 inches of water. 

Outside of containers, this plant's rhizomes can spread rapidly to form colonies under optimum growing conditions. Seeds are carried by water from the plants after blooming. Do not site the plant in natural waterways or in places where floodwaters could carry the plant to natural waterways. The root system consists of a crown with feathery fibrous roots suspended in the water. Clonal daughter plants are often produced by stolons along the surface of the water and form colonies.

Diseases, Insect Pests, and Other Plant Problems:

No known diseases or insect pests. Ability to quickly spread and clog waterways is an issue.