Aquatic Weeds & Their Treatments

Being a pond owner will most likely mean that you will experience some sort of aquatic plants along the way; whether they are wanted or not is a different story!  And how you treat your unwanted aquatic plants is dependent on a proper identification of the plant.

Aquatic plants can be classified into two groups: algae and flowering plants.


Algae are simple structured plants that have no root systems, leaves or any of the other characteristics seen in higher flowering plant species.  There are three general types of algae:  planktonic or microscopic algae, filamentous algae and chara or stonewort.

Planktonic or microscopic algae (shown, right) can be identified by green, blue-green, yellow-green or red colored water known as a bloom.  Blooms can encompass the entire surface of a pond and can resemble a pea soup consistency if left untreated.

Filamentous algae (shown, left) initially form around the perimeter and the bottom of the pond in the spring in a mat-like fashion.  They take on the characteristic of being stringy.  This type of algae is very commonly observed on waterfalls, making surfaces slippery.

Chara or stonewort (shown, right) is easily confused with a flowering plant due to its similar appearance.  However, it is considered algae.   Chara grows best in very hard water and is often calcified and brittle.

Flowering Plants

Flowering plants have several differences from algae.  For one, they are more structurally complex than algae.  In addition to being able to produce flowers, they also have an internal conducting system which algae lack.  Flowering plants are categorized according to where they are found in a body of water: submersed, free-floating, rooted-floating and emergent.  While the category names might differ slightly from one publication to another, there location in the water is still the same.

Submersed plants are rooted in the bottom sediments and grow up through the water with their flowers or flowering spikes and sometimes emerge from the water.  Some varieties of submersed plants have both underwater leaves and floating leaves.   While these plants tend to be quite invasive, they do offer good shelter for game fish.  Some of the most common submersed plants are shown below.

Free-floating plants can completely encompass the entire surface of the pond resulting in oxygen depletion in deeper water.  The plants are found in nutrient rich waters; therefore, restricting nutrient inputs can help to alleviate this situation.

Rooted-floating plants are generally found in shallow water less than 4 to 5 feet deep.  Common varieties are shown below.

Emergent or marginal plants are found along the shoreline line or the margin of a pond.  Many of these plants spread rapidly by underground systems, as well as, by seed.

New on Our Website: Pond Reference Calculators

Check our ever-growing reference area, with our new Pond Reference Calculators, including:  Head Pressure Calculator and Electrical Cost Calculator. 

The Head Pressure Calculator will prompt you for vital questions that will help assure you make a sound decision when it comes to knowing your current pond system’s head pressure. 

The Electrical Cost Calculator can help you determine how much a pump will cost you daily and monthly.  This calculator can be used for ANY electrical appliance.  It’s a great way to determine which pump or electrical product will be the most efficient yet still serve your needs.


Differences between Pond Pumps

Selecting a pond pump can be quite a task when you consider all of the factors that are associated with this purchase.  There are several different categories of pond pumps, which are outlined below.  Each one of these categories serves a particular application best.  Finding the best pump for your application will help assure electrical efficiency, increased pump and less hassles altogether.

Magnetic Drive Pumps

Mag drive pumps, as they are commonly referred, offer more electrical efficiency but are not as powerful.  These sealless pumps transmit torque by magnetizing the impeller.   They find great application in waterfall and streams that meet their low and medium head requirements.  

Direct Drive Pumps

These pumps are more powerful, offering a more maximum head height than mag drive pumps but also use more electricity as well.  They are used quite commonly in larger waterfalls and streams.

Hybrid Pumps

These new generation pumps offer great performance and high efficiency.  They boast that they are low maintenance and extremely quiet.  To date, there are few companies manufacturing these pumps.  

Statuary/Fountain Pumps

These pumps are commonplace in fountains, spitters and other stand-alone applications.  

External Pumps

These pumps are installed outside the pond and are used on larger-sized ponds.  Many of these pumps use priming pots on the intake to assure that the pump stays primed.