Floating Pennywort (Hydrocotyle ranunculoides)

Species

Distribution

Floating pennywort (Hydrocotyle ranunculoides)

Photo courtesy of GB Non Native Species Secretariat

To view NBN location data click here

Impacts

Pathways

• Forms dense rafts and outcompetes native plant species.
• Reduced light levels below the rafts can cause die off of waterweeds and algae and reduce water oxygenation levels
• Deoxygenates water killing fish and other fauna.
• Blocks water bodies and may lead to an increased risk of flooding.

• Trade of garden pond plants
• Dispersal by water flow and flood events.
• Has also been sold incorrectly labelled.

Management

Prevention

Should not be released in the wild. Dispose of garden and pond waste responsibily. Check vehicles, boats, equipment and clothing for plant fragments when leaving infested sites and clean if necessary.

Physical Control

Although care should be taken to remove all cut plant material from the waterbody as rapid re-growth can occur from a single node. Hand pulling or spot chemical treatment should follow cutting to reduce re-growth.

Chemical Control

Herbicides containing diquat or 2,4-D Amine are the most effective for control resulting in extensive dieback of vegetation. Treatment should only be used at the end of the growing season when there are no further submerged apical stemtips. Care must be taken when using herbicides near water. The Environment Agency have produced a guidance booklet that is available here

Biological Control

None

Links

Non Native Species Secretariat Fact Sheet

SNH SAF Training Manual

Invasive Species Ireland Fact Sheet

Invasive Species IrelandManagement Plan

Daisie Species Fact Sheets