Wild About Texas – October, 2007
Just Add Water
Water is a precious commodity for all forms of life in
our hot, dry climate. A water garden, or pond of any size,
can provide hours of interesting observation as dragonflies,
fish, birds, and other wildlife visit your garden oasis.
Finding the right location for your pond should be your
first consideration. It is possible to have a water garden
in considerable shade, but leaves falling from nearby
trees are a maintenance headache. Also note that the largest
selection of colorful plants are those that grow in a
half-day or more of sun.
Add a Container
A pond is any contained area of water that supports a
community of plants and animals. It can be constructed
with a full-scale, permanent concrete shell, reinforced
with rebar and wire mesh, or it could be made with a more
temporary, plastic liner that may last for several years.
A simpler alternative can be to use a galvanized metal
stock tank, a washtub or a sealed clay pot. These vessels
can be set directly on the ground or buried.
After your reservoir is in place, the next thing to do
is add water. If you are using city water, allow the water
to sit for a minimum of 24 to 36 hours before adding plants
or fish to give the chlorine time to evaporate. If you
have rainwater or water from a well, you may add fish
immediately. Note that well water may be low in oxygen,
which is necessary for most organisms to survive. You
can let the water sit for a few days or oxygenate it by
spraying it into the pond as it is added. A sprinkler
works well for this.
You are now ready to add plants. For aesthetic and functional
reasons, you should include a variety of plants that stand
upright, trail or float, and a few that remain submerged
under the surface (these are typically good for adding
oxygen). Tall vegetation, such as horsetail, makes excellent
perches for resplendent dragonflies. These insects provide
captivating lessons on courtship and territorial behavior.
Mat-forming or floating plants, like water lilies or coastal
water hyssop, make good platforms where frogs, butterflies
and other insects can rest, sun and drink from the edge.
Ideally, during the summer, vegetation should cover about
70 percent of the water’s surface. Providing a diversity
of plant forms with flowering periods that range throughout
the season will make the most interesting and ecologically
Unfortunately, most aquatic plants currently available
are not native to our area. While the majority of non-natives
are harmless, some have the potential to escape or already
have escaped cultivation to become noxious and aggressively
invasive. Some of these are even illegal to possess, such
as water hyacinth (albeit beautiful) and water lettuce.
Fish are key to a successful pond. If you have a healthy
fish population, you will not have mosquito problems.
When you are ready to add fish, consider stocking with
mosquitofish or other hardy native fish. Once you are
ready to add them to your pond, set their container into
the water to allow the water temperatures to assimilate.
Slowly add small amounts of pond water to the container
to acclimate the fish to the new water chemistry. This
process should take at least 15 minutes. When the water
temperatures are the same in the container and in the
pond, let the fish swim free.
It is not necessary to feed your fish at all and doing
so may lead to water quality problems. Fish will eat mosquito
larvae and other small aquatic insects as well as some
algae. They will breed until there are too many to be
supported by the available resources; at this point a
few may die and breeding may suspend until sustainable
numbers are again reached.
Maintaining your pond involves only a few activities:
1. Keep the water level constant. Evaporation in the
summer or visits from thirsty animals may require you
to regularly replenish the level. If you fill with chlorinated
water, it is best to add only a few inches at a time.
Wait a day between fillings or use rain or purified water.
2. When necessary, remove string algae and leaves by hand
or with a net.
3. Trim plants that get too large. Dead (or frozen) foliage
is unsightly and can create anaerobic conditions in the
water and should also be cut back.
4. Fertilizing is generally not necessary and may promote
algae growth. If you choose to add nutrients, be sure
to use products that are specifically intended for water
plants and are non-toxic to fish.
Fountains are not necessary for aeration if you have
established plants and a balanced fish population. Moving
water, however, is attractive to people, birds and other
animals. Use a calm trickle, stream or water bell fountain.
Too much splashing is detrimental to some plants and will
repel some insects, such as butterflies.
A flat rock sloping gently into the water can serve as
a birdbath, and for animals that wish to sun themselves,
a rock can provide an ideal resting place. Some creatures
cannot swim, and such a rescue platform can be a valuable
resource. A rock can provide access to the water for animals
such as turtles, frogs and insects and should be protected
from heavy splashing so as not to disturb these visitors.
Be aware that these animals may be put in danger if you
have pets that like to hunt.
A water garden can be relatively easy to maintain, leaving
you time to enjoy it!
A few plants for Texas ponds:
American water willow
Salt marsh mallow
White water lily
Marsh obedient plant
About the author: Andrea DeLong-Amaya is Director of Gardens at Lady Bird Johnson Wildflower Center in Austin. Find out about these plants on the Lady Bird Johnson
Wildflower Center Web site at www.wildflower.org