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Having a water garden allows a gardener the opportunity to grow
a range of plants that can only be cultivated in this liquid format.
These water plants are not only beautiful but they also serve the
important function of minimizing the build-up of algae. Without
them, water quickly turns green and cloudy.
Algae:
Water contains many elements such as salts and nitrates. They remain
there because evaporation is 100% pure. The buildup of these salts
and nitrates is one of the major causes of algae. The good news
is plants absorb both. It's simply a matter of establishing the
right ratio of plants to the volume of water to the point where
water naturally clears and remains that way.
Other causes of algae include too many fish (therefore, too much
fish waste), overfeeding the fish, excessive sunlight, too warm
water temperature, too much decaying organic waste on the bottom,
chemical fertilizers getting into the pond, and excessive movement
of water that brings the bottom waste to the surface.
When you fill your newly constructed pond, let the water sit for
a week. It will probably turn green but never empty the water. It
takes too long to start balancing the delicate eco-system all over
again. After a week, it's safe to start adding your water plants.
They fall into four main categories.
Water Lilies & Lotus:
Water Lilies come in two forms; hardy that can be cut back and left
in the water garden over the winter and tropical that are treated
as annuals or lifted and wintered inside. The major visual difference
between them is that hardy Water Lily blooms sit on the surface
of the water with the foliage while tropical blossoms rise on long
stems well above the leaves. Both are easily grown requiring only
6 hours of sunlight, rich soil, and quiet water. They are placed
45 cm - 60 cm (18" - 24") deep with 20 cm - 30 cm (8"
- 12") of water over the crown of a hardy Water Lily and 15
cm - 20 cm (6" - 8") over the crown of a tropical.
Hardy Water Lilies bloom yellow, red, apricot, white, and pink.
Tropicals are white, pink, red, yellow, purple-violet, and blue.
Don't plant tropical Water Lilies until June when the water temperature
is at least 20°C (68°F).
Lotus leaves and flowers stand 45 cm - 125 cm (18" - 48")
above the water depending on the variety. Exotic, fragrant blossoms
last 3-4 days allowing the unusual seedpod to develop. Lotus requires
many weeks of sunny, warm weather and rich soil to bloom well. Hardy
to Zone 5, it sometimes won't flower the first year.
To overwinter ensure it's at least 3.5 feet deep in your water garden
to protect the tuber from freezing. The leaves of all Water Lilies
and Lotus are attractive as well as very functional. By covering
the surface of the water, they minimize evaporation, reduce light
that algae needs to grow, and keep the water from heating up which
also promotes algae. Combined with other plants on the surface of
the water, aim to cover 60% of the surface.
Floating Plants:
These water plants are classified as "floating" oxygenators.
They liberate oxygen that helps to clear the water and they absorb
excess nutrients that cause algae. Floaters literally float on the
surface with their roots dangling in the water, moving wherever
a breeze takes them. They shade the water and provide protection
for fish. They include Water Lettuce with its soft, velvety, blue-green
leaves arranged in the form of a rosette, Water Hyacinth with its
shiny, leathery leaves and blue flowers, and Duckweed with its tiny
leaves and spreading habit. Duckweed is also food to goldfish. Use
one plant per square metre (yard) of water.
Submerged Oxygenating Plants:
These plants also keep water clear and they control algae naturally.
As well, they provide spawning space for fish and provide shelter
for baby fish. Oxygenating plants are planted in pots that are placed
right at the bottom of the pool. There are many in this category
from which to choose but plan on three plants per square metre (yard).
Marginals:
Planted in shallow water at the edge of a water garden, marginals
soften the edge of your feature and give it a natural appearance.
Hardy shallow water plants include Arrowhead with its distinctive
leaf and spikes of delicate white, three-petalled flowers. Pickerel
Rush produces tight clusters of blue flowers on tall spikes from
midsummer to fall. Variegated Sweet Flag is particularly distinctive
with slender green and cream leaf blades.
There are also tropical marginals some of which can be kept indoors
as houseplants. Others should be treated as annuals and replaced
each year. Read plant signs carefully to confirm. Golden Club is
an attractive aquatic with golden, pencil-like flowers on a white
stem. Taro is noteworthy for its large, exotic looking leaves.
How To Plant:
Sheridan Nurseries Garden Centres sell open weave, black plastic
baskets in various sizes and shapes. Line them first with burlap
or black, porous landscape fabric so soil can't escape and cloud
the water. Use an aquatic soil for water plants and be sure to cover
it with washed gravel, pebbles, or small rocks. That way soil can't
rise, fish can't nose around the top of the container, and the added
weight keeps the planter from popping to the surface. Place each
planted basket in the pond at the required growing depth of each
type of plant. If you need to raise a container higher, say on bricks
or a concrete building block, be sure to place the riser(s) on an
extra piece of PVC to protect the PVC liner beneath from tears.
To eliminate the salt in a concrete block, immerse it completely
in a bucket of water for 24 hours.
It will take several weeks for your water plants to start growing.
Your water will probably be green during that time. Be patient.
There will come a magical moment when the water suddenly clears
and, if it doesn't, keep adding more plants. And don't forget Trapdoor
and Melantho Snails who live solely on algae. They're just as important
to your miniature eco-system as the fish, frogs, and dragonflies.
Also refer to
Gardening Tip #18 - HOW TO
SET UP YOUR POND
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