The popularity of water gardening has increased dramatically in North Carolina and
throughout the country during the past few years, particularly due to the advent of hobbyist
magazines and the appearance of mail-order and on-line plant sales and propagation information.
Water gardens now are major attractions in arboreta and botanical gardens nationwide, and backyard
water gardens have become commonplace. Sales of equipment and plants for water gardens have
nearly doubled annually over the past five years, and industry projections suggest that this rate of
increase will continue for at least another five years. An attractive water garden is an
aesthetic asset and even may be a financial asset in terms of increasing property values.
Closely related to water gardening is another aspect of ornamental landscaping often called
"aquascaping". The aquascaper seeks to beautify the landscape by planting of a variety of interesting
and colorful plants in what otherwise would be rather drab ponds and wetlands. The tightening of
environmental regulations to require vegetated buffer zones to intercept nutrient runoff and retard
soil erosion around new and existing ponds and wetlands, coupled with the desire to beautify these
areas, has led to a significant increase of aquascaping activities on golf courses, in apartment and
other residential complexes, on college and industrial campuses, and in many parks. Sales of plants
for aquascaping are booming in North Carolina and elsewhere in the Southeast, and many of the
nurseries producing aquatic and wetland plants are sidelining as landscape contractors for aquascape
installation. Lake restoration and mitigation activities more recently have drawn the attention of the public
and of the aquatic and wetland nurseries. Sediment removal, aquatic weed management operations,
and wetland creation and mitigation activities are becoming increasingly more common. Any activity
which restructures the shoreline of a lake or reservoir, increases wetland habitat, or removes noxious
weeds, provides new habitat suitable for colonization by vegetation. Quite often the colonizing
vegetation is invasive in nature (e.g., dense stands of cattails, noxious water weeds such as hydrilla,
smelly growths of filamentous algae, etc.) and creates problems unless proper management strategies
are implemented. One approach to this situation has been to plant desirable species before the new
habitat is colonized by the undesirable ones. In theory, these plants would colonize the available
space and provide competition that will retard the establishment of undesirable species.
Simultaneously, revegetation with desirable species would prevent shoreline erosion and be
aesthetically appealing. Aquatic and wetland plants for water gardens, aquascaping, and lake restoration until quite
recently have been purchased largely from out-of-state nurseries, as few sources were available within
North Carolina. This has presented several problems, including the introduction of species that are
unsuited for their new environments and others that may become weeds. The increasing availability
of plants from mail-order and on-line catalogs has only aggravated this situation. The demand for water and wetland plants has spawned the growth of aquatic plant nurseries
in a number of locations in North Carolina. These new nurseries, in turn, have obtained most of their
stock from out-of-state sources. A few also have permits and are collecting locally. In some cases,
the nursery stocks purchased from other nurseries as well as locally collected plants contain
undesirable, invasive species such as hydrilla as contaminants. Occasionally a contaminant species
looks interesting and ultimately becomes cultivated and sold by the industry. A number of undesirable
species (e.g., giant salvinia) have been cultivated, sold, and distributed widely, either mistakenly or
intentionally, under the under the wrong scientific and common names. Most of the plants sold for water gardens and aquascaping, are not native to North Carolina
or the United States. The great majority of these plants never become problems. However, a few
have proven to be highly invasive (e.g., waterhyacinth and purple loosestrife) and have caused
significant environmental damage through habitat destruction. These species crowd out more
desirable native plants and may result in elimination of the types of habitat needed by aquatic
invertebrates, fish, and wildlife. Their economic impact also may be devastating. Dense growths of
invasive aquatic and wetland plants obstruct navigable waterways, restrict drainage, clog water
intakes, degrade water quality, and interfere with fishing and recreation. Preventing the introduction and spread of noxious aquatic weeds can save millions of dollars
of public and private money annually which would be spent for economic losses and control activities.
Just because a plant is interesting or has a pretty flower does not constitute justification for releasing
it into the environment when it has a history of being invasive. Invasive species including giant
salvinia and hydrilla (both Federal Noxious Weeds), creeping waterprimrose and purple loosestrife
(NC Noxious Weeds), are not native to the United States and have entered either as contaminants
among other plants or as intentional introductions. These designated federal and state
noxious aquatic weeds are regulated under a combination of Federal Noxious Weed Laws, North
Carolina Noxious Weed Laws, and the
NC Aquatic Weed Act of 1991. The Aquatic Weed Act of
1991 specifically empowers the North Carolina Department of Agriculture and Consumer Services
and the Department of Environment and Natural Resources jointly with the authority to regulate the
importation, possession, propagation, distribution, and sale of illegal aquatic plants. Several other
non-native species including Brazilian elodea and parrotfeather, are highly invasive but
currently are not regulated in North Carolina. Even some native species including cattails,
waterlily, lotus, duckweed, and mosquito fern, may become invasive if planted or allowed to escape
into ponds, lakes, streams, and wetlands. One tiny, native, free-floating plant, watermeal, is a
common contaminant of aquatic and wetland nursery stock and is extremely invasive and difficult to
control if allowed to escape into ponds. It has become one of the four or five most common and
troublesome weeds in irrigation ponds throughout North Carolina and the Southeast. All of the plants mentioned above have one very important characteristic in common: they are
highly invasive weeds when allowed to become established in ponds, lakes, and wetlands. With the
exception of hydrilla and watermeal, all (including giant salvinia, illegally) are being sold widely for
water gardens and aquascaping. The free-floating species ( waterhyacinth, giant salvinia, mosquito
fern, duckweed, watermeal) are easily moved from site to site by water currents, birds and mammals
(including people) to become problems. The underwater plants ( parrotfeather, Brazilian elodea, and
hydrilla) will completely overtake shallow ponds, lake margins, drainage ditches, and canals. Hydrilla
and Brazilian elodea may form dense surface mats in water 10 feet or more in depth. Is this what
YOU want in your ponds and lakes? And how about the monetary investment that went into buying
and planting these plants? And how much are you willing to spend to get rid of those plants which
become weedy? Careful consideration of the nature of the plants you plant to put into a water garden,
aquascape, or wetland can reduce the likelihood of inadvertently creating an eyesore or
major weed management problem. Most of the ponds and other areas that are to be "beautified" with
plantings of aquatic and wetland vegetation are very shallow (many are less than three feet deep) and
receive runoff from highly managed turf. The combination of clear, shallow water and substantial
nutrients in the runoff water create the very conditions most conducive to the rampant growth of
filamentous algae and invasive plants. A wise approach is to select native vegetation whenever
available and to plant only those species which usually are not invasive. Plants such as
blue-flag iris, pickerelweed, horsetail or scouring rush, soft rush, several species of spikerushes,
lizard's tail, arrow arum, and arrowhead are native, have attractive foliage and/or flowers, are easily
established and well adapted to the North Carolina environment, and usually do not become serious
problems (i.e., they are easily managed). They all are perennial, overwinter nicely, and are available
from in-state aquatic and wetland nurseries. The best assurance of having attractive, trouble-free water gardens, aquascapes, and wetland
plantings is careful plant selection. Educate yourself about the nature of aquatic and wetland plants,
and know what you want before you purchase. Beware of salesmen who seem too eager to sell you
large numbers of expensive, pretty plants and who assure you that they are not invasive and will never
become troublesome. Even when purchasing native plants from local sources, be sure your plants
are free of unwanted contaminants. This means that you must examine the plants you buy very
carefully before planting. Visit the nursery and look at the plants they have for sale and whether or
not there are other plants mixed in with them. If you should find contaminants such as duckweed,
watermeal, or others, do not accept the plants. Also be sure that your source of plants is a state
certified nursery or dealership. When planting water lilies, lotus, and cattails, use only containerized
plants; this reduces the likelihood that they will spread into areas where they are unwanted.
Whenever you feel that you may have a problem, consult a qualified specialist for assistance. Further
information may be found at the NCSU Aquatic Weed Management website at: http://www.cropsci.ncsu.edu/aquaticweeds This site also has links to on-line publications and other websites related to aquatic plants and their
management. For additional photos of aquatic and wetland plants, see the University of Florida's
website: http://aquat1.ifas.ufl.edu/photos.html.
