Herbicides - Ponds benefit from natural growth which can also provide food for livestock in the water, but too much plant growth can also be detrimental to the ecology of a pond. When choosing an herbicide for weed control there are several choices. Liquid and granular herbicides can be used for spot eradication of unwanted or unruly weeds and those that are concentrated may mean fewer applications over the course of a season. They can also be used for submerged and floating plants. Application will depend on the target weeds and their location as well as the depth of the water in which the weeds are growing.
Pond Dye - Cloudy water in a pond is rarely a welcome sight and it can take time to investigate and find the reason and even more time to eliminate the problem. Pond dye can be an attractive alternative to living with unsightly water until you get it corrected. The dye not only changes the color of the pond water it can also help with weed control efforts. The dyes serve to filter UV light from the sun stunting weed growth. Dyes are made with food-grade ingredients making them safe for fish, plant life and for swimming.
Pond Algae(3 Common Types)
Filamentous algae is most common, growing in mats and strings.
Planktonic algae causes green water, it has millions of cells that cloud together.
Chara algae is weed-like, it grows like a carpet along the bottom.
Cattails & Other Emergent Plants - Emergent plants grow around the perimeter of a pond in shallow water with all or most of their foliage above water. Examples are Cattails, Bulrush, Reeds, Purple Loose Strife, Pennywart and Pickeralwood.
Pondweeds - The pondweed family has over a dozen varieties with these four being the most common: Sago, Clasping Leaf, Curly Leaf, Large Leaf.
Elodea - This plant grows in thick clumps and is usually not a big problem, the leaves are in whorls of three around the stem.
Duckweed & Watermeal - Duckweed is hard to control, it forms a thin layer over the surface in calm ponds. It will not grow well in moving water so use of a surface aerator will help in controlling growth.
Waterlilies - Waterlilies can become a problem in many ponds, they grow off of a large central root system (much like popal trees). Some growth is great for shade and cover for fish, but when left unchecked they will overpopulate quickly.
Eurasian Milfoil - Spreads very easy since fragments of plant can re-root and grow. Do not try to remove by raking.
Other Less Common Weeds: Include Naiad, Coontail, Bladderwort, Hyrdilla, Parrot Feather & Water Hyacinth.