Hornwort

Hornwort scientific name is Ceratophyllum demersum. It is sometimes called Coon Tail. It looks similar to Tanwort but has a compact flower that does not rise to the surface.

Hornwort is a rootless plant that will lie on the bottom of your outdoor Koi pond in 1-3 feet of water.

It earned its name from the narrow leaves along the stem that resemble the hairs on a raccoon’s tail. It makes an excellent breeding area for Koi fish, and goldfish love to eat it.

Hornwort is unrooted so it doesn’t require planting, and excessive growth is easy to eradicate. Depending on the water’s hardness, Hornwort or coontail may form very soft, delicate leaves, or rather stiff, bristled leaves. This texture makes Hornwort less prone to snail predation.

Hornwort is one of the top oxygenating plants. It is tolerant of a broad range of conditions. In the fall the compact tips break off the hornwort and lie dormant for the winter.

The coontail has been known to release certain chemicals that naturally prevent some forms of pond algae growth, making it a prime addition to the garden pond.

Hornwort is a submerged plant, growing in still or very slow-moving water in ponds and streams. They have numerous side shoots making a single specimen appear as a large, bushy mass. The leaves are produced in swirls of six to twelve, each leaf is 8-40mm long, simple, or forked into two to eight thread-like segments edged with spiny teeth; they are stiff and brittle.

It is monoecious, with separate male and female flowers produced on the same plant. The flowers are small, 2mm long, with eight or more greenish-brown petals; they are produced in the leaf axils. The fruit is a small nut 4-5mm long, usually with three spines, two basal and one apical, 1-12mm long.

The hornwort is often used as a floating freshwater plant in both coldwater and tropical aquaria, though it may attach itself to the objects in the pond by it’s roots. It’s fluffy, filamentous, bright-green leaves provide excellent cover for newly-hatched fish. It will grow and spread out by pruning.

Duckweed

Duckweed is the common name for Lemna Minor. Opinions differ when it comes to Duckweed usefulness. I’m going to give you the facts (from Wikipedia Encyclopedia) and you can decide. I have never used this plant in any of my ponds. I included only for your knowledge of plant species.

It is a floating freshwater plant with one, two or three leaves each with a single root hanging in the water. It propagates mainly by division, and flowers are rarely produced.

It grows in water with a high nutrient level. Growth of colonies is rapid, and the plant frequently forms a complete carpet across still pools when conditions are suitable.

Duckweed is often used as a plant in both coldwater and tropical aquarium as well as in outdoor ponds, though Duckweed must be frequently cut back because of its rapid growth rate and may be considered a pest. It is also grown as a commercial crop for animal feed, primarily for fish and poultry, as it is fast-growing and easy to harvest by surface swimming.

Duckweed shades out other plant species below it by covering the whole surface of the top of the water. It absorbs much of the surrounding resources as possible so that it has the energy to grow and reproduce.

If you have Duckweed in your pond and you want to GET RID OF DUCKWEED there are a couple of things you can do. Put your garden hose in your pond and let it fill up to over flowing then the duckweed will float away with the water.

You will need to get rid of very last fragment. Larger Koi and goldfish love to eat duckweed so if you reduce the amount of food you give them it will encourage them to eat it. Try and get rid of as much of the Duckweed as possible when you overfill the pond so it will give your fish an advantage.

Reference: Wikipedia Encyclopedia

Reference: Encyclopedia of Water Garden Plants