What does it look like?
Senegal tea is a hardy, semi-aquatic perennial herb commonly found in damp environments. It typically establishes itself along the edges of waterways but is also capable of surviving and continuing to grow when fully submerged. Suitable habitats include wetlands, stream margins, and degraded watercourses.
The plant can form rounded bushes up to 1.5 metres tall or spread as scrambling mats of tangled stems across water surfaces. Its leaves are opposite, shiny, and hairless, while the hollow stems are buoyant and float. Distinctive white, clover-like flowers appear from November through to April. Although it resembles alligator weed or willow weed, Senegal tea can be distinguished by the bluntly serrated margins of its leaves.
During winter, the plant becomes dormant and may die back to its rootstock, but it reliably resprouts in spring.
Why is it a problem?
Senegal tea is a fast-growing, semi-aquatic plant that can quickly dominate water bodies by forming dense floating mats of stems. These mats displace and outcompete native aquatic vegetation, leading to significant ecological disruption. Infestations can also block drainage channels, worsen flooding and impact recreational activities and irrigation systems.
The plant reproduces both vegetatively and by seed. Stem fragments or detached leaves readily develop roots and establish new growth. Although seed production is limited, the seeds are long-lived and capable of dispersing effectively, contributing to the plant’s persistence and spread.
Control methods
If you think you have found Senegal tea, contact us at biosecurity@hbrc.govt.nz or 06 835 9200.
Watch our senior biosecurity officer talk through how to identify Senegal tea
More information
Senegal tea is listed as an Exclusion pest under the Hawke’s Bay Regional Council Pest Management Plan 2018 – 2038.
Senegal tea was first identified in 2024 within Te Awa o Mokotuarāro (Clive River). Since then, the infestation has been confirmed to extend into the Karamū Stream. These two locations are currently the only known sites of Senegal tea in Hawke’s Bay.
Related links
Management Programme
National Pest Plant Accord (NPPA)
The NPPA is designed to prevent the sale, distribution and propagation of a set list of pest plants (the Accord list) within New Zealand. If allowed to spread further, these pest plants could seriously damage the New Zealand economy and environment.
More informationUnwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
Exclusion Programme
To prevent the establishment of the subject, or an organism being spread by the subject, that is present in New Zealand but not yet established in an area.
Taxonomies
FamilyAsteraceae
TypePlants
GroupFloating
HabitatFreshwaterLand
Management ProgrammeNational Pest Plant Accord (NPPA)Unwanted OrganismExclusion Programme
