University of Vermont Extension
Department of Plant and Soil Science
Dr. Leonard Perry, Extension Professor
University of Vermont
Small water gardens and ponds can add
beauty and tranquility to gardens.
Proper location, installation, choice of plants, and care will ensure
your water feature lasts for many years with a minimum of problems.
On a larger scale, you can create a water
garden by digging a pond or small pool. For the most variety of plants,
should make it a minimum of about 2 feet deep and 4 to 6 feet across.
hole is dug, line it with 2 to 3 inches of sand, with a PVC pool liner
Black plastic can be used, but use a thick grade and several layers.
keeps the bottom of the liner from contacting rocks and being
On top of the liner you can place thick
black felt pond liner. This felt keeps washed river stone, which you
wish to add, from puncturing the liner from the top. If you're going to
pond pump, underwater lighting, fountains, or blocks for your pots, now
time. Many of these supplies can be found at local home and garden
stores, larger garden centers, or from mail order sources (look for
in garden magazines).
The edge of the pond can be finished with
bricks or flat stones such as slate for a more formal effect. Simply
around the pond, over the edge of the liners. Native stones placed
will give a more informal edge, just make sure they are stable.
Tub gardens can be created from whiskey
barrel halves, lined with plastic or rigid liners made
specially for this purpose. Old plastic trash cans, halves of plastic
large ceramic pots, metal or plastic cattle troughs are other sources
gardens. Attractive barrels may be left on the ground, or the less
ones sunk about level with the surface. If sinking, keep the edge a few
above the ground to keep soil from washing in.
Most the plants will be in pots, sunk in
the water. Depending on the plant, you can place them at various
means of various heights of blocks or bricks placed underneath them.
digging a pond, create stepped terraces as various levels. Water lilies
instance might be placed a foot below the water's surface. Place
oxygenating grasses on
the bottom. Place other perennials in pots just below the water's
surface. Make sure and check your state list of
invasive water plants so you don’t use them.
These may include flowering rush, watermilfoil, frogbit, parrot
purple loosestrife, yellow floating heart, and yellow iris.
Algae is one of the few problems in tub
gardens, and is seen as green growth in the water. This often happens
spring and early summer with higher light and warmer temperatures. Once
balance of enough plants, and perhaps other life is established, it
clear. The other life includes tadpoles or snails. If algae forms
can be removed with a notched stick of piece of rough wood, poked into
mass, twisted, then drawn to the side and out. A filtration system, as
pools, can help remove free-floating algae.
Soil for water plants consists of two
parts ordinary garden soil and one part well-rotted cow manure. If
use equal parts garden soil and pond muck (the soil from the bottom of
If neither muck nor manure are available, add a half cup of bonemeal
of soil. Avoid more fertility as this will only increase the algae.
planted, line the top two inches of the pot with sand or washed gravel.
helps prevent algae growth.
Most pots can be used for plant
containers, but should be large enough for the plants grown.
Special wooden pots (cedar or cypress) or perforated plastic cages or
baskets are often used. I use clay pots
that I make sure and remove in winter when I drain my small pond.
Some water plants withstand freezing but
most don't. Even the hardy water lilies will survive if in large ponds
the ice, but not if frozen. For most smaller water features in the
the pots of lilies and water plants indoors for the winter.
In late fall remove the containers of
plants, cleaning off the old leaves and dead foliage. If you won't be
back into tubs of water indoors, let pots drain overnight. Then place
plastic bags left open at the top. Move aquatic plant pots to a garage
cellar where they won't freeze, such as at 32 to 35 degrees F. Keep
letting them dry out, over winter. For
me, tropical water plants such as water hyacinth and water lettuce need
light and air temperatures about 55 degrees (F) or above, in a small
water, to overwinter successfully. Place
back outdoors in your water feature in spring, once freezes and frosts
and you have cleaned it.
Large water features, such as ponds, in
the north will need to be deep enough to not freeze if hardy water
fish are to be left in them over winter.
This may be a minimum three to five feet deep, depending on your
zone. Keep in mind that in some cities
and towns, ponds deeper than 18 inches may be considered pools and so
be fenced. If ponds aren’t deep enough,
or start freezing anyway, try either a pond heater or a plastic ball on
pond surface. As the wind moves the ball
around, it will keep the surface from freezing.
Much more on pond types, accessories, and
all aspects of successfully installing a pond can be found in the
Garden Supermart (www.gardensupermart.com).
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