Aquatic Gardening Construction and Maintenance

Aquatic plants have been an important part of gardens since early
history when they were first used in ancient gardens of the Far East,
Egypt and India. Early herbalists extracted tannin from the roots of
water lilies to calm a variety of nervous and digestive disorders.
Many water lilies also provided some of the earliest fabric dyes
which were extracted from their roots.
Contemporary aquatic gardening has received a lot of attention by
homeowners and commercial landscapers. The development and
increased availability of various types of preformed pools, flexible
liners and other containers has helped to foster the current increased
enthusiasm in aquatic gardening. These new materials are a great
improvement over the old tedious process of building pools out of
concrete.
The style and size of a water garden can range from a simple above
ground tub garden, a small preformed pond, or to a large pond
constructed with a flexible liner.
Pond location
The first step in designing a water garden is to consider where it
will be enjoyed the most. Some good locations for a pond are near
a patio, deck or within view from a window. A pond can be either
formal or informal in shape. Informally shaped ponds are the most
popular. Some common shapes are the classic kidney bean and the
figure eight.
In addition to locating the pond for best viewing a pond should be
located where it will receive at least five or six hours of direct sun
if flowering plants are desired. As the hours of direct sunlight
decreases, so do the blooms. The hardy and tropical bog plants
will perform best in semi-shaded sites. It is generally recommended
to avoid locating the pond directly under trees because of the leaves
and other debris that will fall into the pond. Also, avoid locating
the pond in a low spot because surface runoff may wash mud, lawn
fertilizers and pesticides into the pond.
Pond Construction
A pond can be made almost any size or shape desired if a flexible
liner is used. If a rigid preformed pond is chosen the size and
shape will be limited by what is available on the market. The
depth of a pond should be at least 18 inches in the center for the
successful over-wintering of hardy aquatic plants. A shallow ledge
should be provided along the outside edge of the pond for placement
of potted marginal plants. These plants cannot tolerate growing in
deep water. Make the ledge about 10 inches below the surface and
wide enough to submerge potted plants in a stable manner.
Installing a Flexible Liner
The development of flexible pond liners has done much to make
pond design and installation easier. It has played a major role in
the growing popularity of aquatic gardens. A flexible liner is a
thin rubber-like material cut from a large roll of material. Its
flexibility allows it to conform to the contour of any size and shape
desired. When properly installed, these liners will last for many
years.
There are three types of flexible liners on the market: polyvinyl
chloride (PVC), butyl rubber and ethylene propylene diene
monomer (EPDM). PVC liners were one of the first liners to be
developed. It ranges in thickness from 20-32 mils. PVC liners are
the least expensive and will last 7 to 10 years. The most limiting
factor of its durability is exposure to the sun. PVC is only moderately
resistant to the effects of ultraviolet radiation and will eventually
crack when exposed to prolonged sunlight. Always keep the pond
filled to the top to prevent the liner from being exposed to direct
sunlight.
Butyl rubber has also been used for a long time. It is a highly
recommended synthetic rubber liner because of its resistance to
ultraviolet radiation. It has a useful life of 20 years or more. It is
30 mils thick. It is easier to work with than the stiffer PVC liners
because it is more flexible.
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A more recent entry into the pond market, which is very similar
to butyl rubber, is EPDM. This is also a type of synthetic rubber
that is less expensive than butyl and has the same appearance and
durability. It is the thickest liner available (45 mil). It is a dark
charcoal gray or black and quite flexible and easy to install. EPDM
was originally used in the roofing industry and was manufactured
with an antifungal mineral talc coating. Some problems of fish
toxicity have been reported with earlier EPDM. The products
marketed as fish safe EPDM do not have these mineral talcs and
are very safe to use for ponds.
Determining Liner Size
Flexible liners are cut from rolls that may be 10, to 25 feet or
more in width. To determine the size of the liner required, determine
the length and width of the proposed pond. Next determine the
maximum depth in feet and multiply this by 2. Add this amount to
both the length and width. Finally add at least one additional foot
to both the length and width for the top edge overlap.
Formula:
For additional protection use a spun underlayment material made
for this purpose. Rug padding or several layers of wet newspapers
can also serve as a cushion under the liner.
Carefully spread the liner to fit the contours the best you can to
make the liner conform to the excavation. Don’t worry too much
about the unsightliness of the folds. They will lay flat with the
weight of the water. When the pool is filled with plants, these
folds will be difficult to see. Gradually fill the pond with water as
the liner is folded into place.
Installing a Rigid Liner
Actually almost any water tight container if large enough can be a
potential water garden. Many things, such as large ceramic pots,
plastic horse trough, child’s swimming pools, half whiskey barrels,
etc., are suitable for above or below ground. New whiskey barrels
should be aged by filling with water, emptying and refilling until
the odor of alcohol is gone. There are plastic inserts that may be
used in them to avoid the toxic effect of the alcohol. To assure the
successful overwintering of hardy plants in above ground containers,
install a stock tank or pond heater.
Using a rigid liner has merit because it is tough, durable, quick
and easy to install, has a life expectancy of over fifty years (for
fiberglass) and comes already molded into various shapes. Other
types of preformed liners are made of molded semi-rigid plastic
which are less expensive but also less durable than fiberglass. As
with the flexible liners all sharp objects should be removed and
the excavation be lined with an inch of sand. After the site
preparation, place the pool so that the rim is slightly above the soil
line. Level the pool from side to side using a carpenter level.
Place soil around the pool exterior while filling the pool with
water. This will help reduce stress on the pool as it is being filled
with water. Edge the top with flat stones.
Constructing a water garden is really not a very difficult task.
When the proper site has been selected and the pond properly
installed, it will provide you with years of beauty and enjoyment.
Liner width = pond width + 2x depth + 1 ft.
Liner length = pond lenght +2x depth + 1 ft.
The extra 1 ft is to allow sufficient quantity of the liner to go
under the edging stones and behind them. Do not trim the liner
until the pond is finished and the water level is adequate. Allowing
the water level to submerge part of the rock edging helps to make
a very natural-looking edge.
Remove all sharp objects like stones and tree roots to protect the
pond liner from puncture. These lines are very tough but if a
puncture or tear should develop, it is easily repaired with a pond
liner repair kit.
INSTALLATION OF A FLEXIBLE LINER
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Pond Maintenance Tips
Like any garden worth keeping, there is some basic maintenance
techniques to practice. In the spring remove any debris that may
have fallen into the pond during the winter. If there is an excessive
accumulation over many years, the pond will have to be drained
completely to remove this material.
Water lilies and other aquatic plants grow very rapidly and, in
time, become crowded, reducing their vigor and bloom. Every
two to three years they should be lifted from their containers and
divided in the spring as new growth begins to appear. Give them
their first fertilization at this time.
In the summer, remove dead plant debris. Water lilies, in particular,
continually have older leaves dying as new leaves emerge. Excessive
plant growth may need to be removed to make viewing the fish
possible. Continue to fertilize lilies during the summer.
Occasionally, insects specific to aquatic plants, such as the water
lily aphid and the water lily beetle, will invade the pond. Fortunately
their destruction is usually not very severe. Their are no registered
pesticides for home aquatic ponds. Simply dunk the leaves in the
water or hose off the aphids. The fish will enjoy eating them.
The water lily beetle is easily controlled by removing infested
leaves. This will break the life cycle.
In the fall cut back the frost-killed tops of the hardy plants. The
tropical plants can be discarded. Stop feeding the fish when the
water temperature drops below 55 degrees F, this usually occurs
in mid to late November. Move all plants into the deeper area of
the pond (18 inches) for freeze protection. If the pond is in a
location where tree leaves might fall into it, cover the pond with
chicken wire.
And lastly, if there are fish in the pond, install a floating stock
tank heater to keep a small portion of the pond free of ice in the
winter. This is an automatic deicer than comes on when the
temperature is a few degrees above freezing. A heater of 1500
watts is recommended for Maryland winters. One word of caution,
the fish will group around the heater and those that get pushed
against the heater element get burned. A good heater will have a
small guard panel to keep the fish from touching the heating
element. The fish will benefit from this ventilation hole which
allows oxygen to enter. However in larger ponds the heater will
freeze in place during very cold winters. If the pond should freeze
over do not try to crack or break the ice. The shock may injure the
fish.