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
All plants on MPI's National Pest Plant Accord (NPPA) are unwanted organisms under the Biosecurity Act 1993 whose formal or casual trade contributes significantly to their spread.
Plants on the Accord cannot legally be propagated, distributed, or sold in New Zealand. If allowed to spread further, these pest plants could seriously damage our economy and environment.
Unwanted 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.
More informationExclusion Programme
Exclusion pest plants are organisms known in other parts of the country but are not thought to exist in Hawkes Bay. An Exclusion Programme aims to prevent a specific pest from establishing in the region before it arrives. With economic returns of around 1:100, prevention is always the most cost-effective strategy available. The faster we can detect an incursion, the more economical and successful our response efforts are likely to be. If an organisms listed under an exclusion programme was to establish, it has the potential to cause adverse effects on production, economic wellbeing, and environmental values.
More informationRules
Section 26ZM of the Conservation Act (1987)
In accordance with the Conservation Act 1987 section 26ZM, no person shall transfer live aquatic life or release live aquatic life into any freshwater. This includes native or introduced fish, plants, and invertebrates. The taking and holding of some organisms requires a special permit from MPI.
More informationTaxonomies
FamilyAsteraceae
TypePlants
GroupFloating
HabitatFreshwater
Management ProgrammeNational Pest Plant AccordUnwanted OrganismExclusion Programme
