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Escaped water plants are a threat to water bodies in Gwinnett

There are many exotic plant species that can damage Gwinnett County waterways. Water hyacinth, water lettuce, hydrilla, watermilfoil, aligatorweed and lotus are all introduced plants that can be serious pests in our waterways.

These same plants are sold in nurseries as ornamental pond plants. They escape when birds visit koi ponds and then fly to native water. Seeds and plant parts stick to the animals' legs.

Other times, people think these beautiful plants would improve our ponds and lakes. They pitch a few into a pond, inadvertently creating a big problem. In several of our parks, for instance, shortsighted citizens have introduced water hyacinth into ponds. These infestations have become very serious and have cost individual pond owners and the Gwinnett taxpayers money to clean up.

Aquatic weeds are undesirable in ponds for several reasons. They provide cover for small bream, which results in overcrowding. Weeds use nutrients, and they can become so abundant that boat traffic or fishing becomes difficult.

Common invasive plants

Sacred lotus, which has pink flowers and is an introduction from Asia and Australia, has taken root in several locations after being cultivated as an ornamental. The lotus has stiff, 5-foot stems supporting leaves that resemble inverted umbrellas, and large, pink, fragrant flowers that appear in summer months. Once established, the species forms large colonies. Since the lotus holds the world's record of seed viability - 1,300 years - it can stick around for a while.

Parrots feather is an invasive water plant that is sold widely at pond plant retail outlets. It's a feathery aquatic plant with stems that can grow up to 6 feet in length, and the tips of the stems frequently protrude from the water up to 18 inches. The short leaves grow in tight whorls and are shades of bright yellow and green.

The Parrots feather plant's attractiveness disguises its aggressive nature. The plant is capable of totally choking waterways, excluding all other flora and fauna. Usually humans spread the plant, but in this case we believe it was spread to the pond by waterfowl. I have seen it in several ponds on Gwinnett County parks, as well.

Water hyacinth, a floating aquatic plant used in many home water gardens, is a potentially devastating invasive plant. Many people mistakenly believe the plant does not survive the winter in our region.

Water hyacinth is a floating weed. The plant reproduces rapidly and prodigiously by division. Little plantlets grow from the parent plant and break off to form new plants. It also produces seeds that can germinate the following year. The infestation has taken several years to reach their current proportions.

Keeping plants

from invading

Everyone should take precautions to prevent the spread of noxious exotic aquatic weeds into our reservoirs.

Never release any water plant into native watersheds. These weeds have the potential to choke waterways, devastating native wildlife habitat and clogging our wetlands, streams and rivers.

Make sure ornamental water plants are properly disposed of when you remove them from backyard water gardens or aquariums. Compost them or put them into trash bags for pickup.

If you take your boat to some other state, such as Florida, where water pests are prevalent, thoroughly sanitize your boat before putting it into any Georgia waterway.

Never collect water plants from what you think are wild populations and spread them. Noxious water plants multiply rapidly so use some caution when giving them to friends.

If you know of any suspicious water weed infestations in Gwinnett County, please call the Gwinnett County Extension Service at 678-377-4011.

Timothy Daly is an agricultural and natural resource agent with the Gwinnett County Extension Service. He can be reached at 678-377-4010 or timothy.daly@gwinnettcounty.com.