Waterscapes 101

Coontail Hornwort Submerged Pond Weed

Ceratophyllum demersum is a non-rooted aquatic plant that grows underwater. It is commonly known as coontail or hornwort. Stems can grow up to 11 feet long! It produces stiff and spiny green needle-like leaves.

It's often confused with watermilfoil. Milfoil has more feather-like leaves and is more delicate. Click here to read more about watermilfoil

Where does coontail grow?

Plant growth occurs slow moving or calm water of lakes and ponds. It can grow in water deeper than 6 feet. Coontail can continue to grow throughout winter months when other aquatic vegetation dies back.

coontail-pond-weed
Ceratophyllum demersum

Is coontail invasive?

Ceratophyllum demersum is a native aquatic plant throughout the US.  It provides a number of benefits to ponds including fish habitat and nutrient uptake.

Because there is no root system, coontail can take over a pond if left unmanaged. Rapid growth occurs when there are excess nutrients (nitrate and phosphate) in water to feed the plant.

Can I manually remove hornwort?

Ceratophyllum can be removed with rakes. Weeds will reproduce through fragmentation. It is important to remove all vegetation. Once removed you don’t have to worry about regrowth because there is no root system to reestablish.

Best treatment for coontail weed control:

Aquathol K provide excellent control of coontail. This treatment yields quick results and has no water use restrictions.

Sonar provides a long term management solution for coontail hornwort. Sonar reacts slowly, taking 30-60 days for results. The entire pond must be treated for success. This treatment option is only for ponds with little or no flow coming into the pond. Sonar AS, and Sonar RTU are available options

Other treatment options:

Tsunami DQ provides fast control. To improve results, mix with Cutrine (1 qt Tsunami, 1 gal Cutrine). This is a contact herbicide. Must come in contact in order to kill.

Navigate granular herbicide is a good treatment option. Early season control is ideal.

Coontail Treatment Options