Quick Facts

Quick facts

• Senegal Tea Plant (Gymnocoronis spilanthoides) is a highly invasive aquatic weed occurring in scattered infestations around the country.
• It blocks drainage channels and degrades natural wetlands by displacing native plants and animals.
• Preventing its further introduction and spread will require greater public awareness of how to identify it and the risks that it poses.
• Contact your state or territory weed management agency or local council if you find Senegal Tea Plant. Do not attempt control on your own, as it can spread very easily from dislodged fragments.

What Does It Look Like?

What is it?

Senegal Tea Plant (Gymnocoronis spilanthoides) can grow as an erect, rounded bush up to 1 m tall, but is more commonly found as a scrambling form extending from the edges of waterways, and forming dense tangled mats in open water. Young stems are 5-10 mm in diameter, increasing to 20 mm with age. Larger stems are hollow between the nodes (the joints between segments of stem) and float on water, and can reach a length of 1.5 m. The leaves are dark green, 50-200 mm long and arranged in opposite pairs along the stem. The edges of the spearhead-shaped leaves are serrated.

The numerous, white or purplish-white, ball-shaped flowers, 15-20 mm in diameter, occur at the ends of stems.

The ribbed seeds are yellow-brown and 5 mm in diameter. Thin, fibrous roots can develop at any node that is in contact with moist soil or immersed in water (CRC 2003).

For further information and assistance with identification of Senegal Tea Plant contact the herbarium in your state or territory.

Flower colour

White

Growth form (weed type/habit)

Aquatic

Where it currently grows? Preferred habitat

Senegal Tea Plant grows in wetlands, particularly degraded waterways. It can flourish in still or slow-moving fresh water, rooted in the bank and floating out into the waterway. It survives and continues growing even when completely inundated. It also grows on wet marshy soils near water. Senegal Tea Plant grows very quickly in fertile environments, with growth rates exceeding 150 mm a week (CRC 2003).

Are there similar species?

Senegal Tea Plant may be confused with Hygrophila costata (Hygrophila) and occasionally with Chromolaena odorata (Siam Weed), Ageratina adenophora (Crofton Weed), and Ageratina riparia (Mistflower). Navie (2004) provides the following guide for distinguishing between these species.

Senegal Tea Plant is an aquatic plant with somewhat hollow stems and narrowly egg shaped (ovate) or lance-shaped (lanceolate) leaves with finely toothed (serrated) margins. Flower heads are 15-20 mm in diameter and are white or purplish white and borne in clusters at the tips of the stems.

Hygrophila is a semi-aquatic plant with stems that are not hollow. Leaves have entire margins. Flowers are white about 10 mm in diameter and stalkless and are borne in small clusters in the leaf forks (axils).

Siam Weed is a large terrestrial plant with stems that are not hollow. Leaves are egg shaped or triangular with slightly toothed margins. Flower heads are relatively small, about 3 mm in diameter, pale pink, mauve or whitish in colour and borne in dense clusters at the tips of the branches.

Crofton Weed is an erect terrestrial plant 1-2 m tall with stems that are not hollow. Leaves are relatively broad with slightly toothed (crenate or serrate) margins. Flower heads are relatively small 5-7 mm in diameter, and are white in colour and borne in dense clusters at the tips of the branches.

Mistflower is a creeping or scrambling terrestrial plant 40 -60 cm high. Stems are not hollow. Leaves are relatively narrow with toothed margins. Flower heads are relatively small, about 5 mm in diameter, are white in colour and borne in dense clusters at the tips of the branches.

Why Is It A Weed?

What are its impacts?

Senegal Tea Plant is on the Alert List for Environmental Weeds, a list of 28 non native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia's ecosystem.

Native ecosystems: Senegal Tea Plant poses a significant risk to the health of wetland ecosystems. It can quickly take over wetlands and detract from their environmental value, natural beauty and recreational potential. In New Zealand it has caused flooding by blocking streams and drainage channels. It could potentially infest wetlands throughout much of Australia. It has a wide climate tolerance and has been found in cultivation well outside its predicted range. It is also very difficult to control because it can spread by both seed and vegetative reproduction, with even tiny pieces of vegetation giving rise to new colonies. Because it is found mainly in water, the potential impact of herbicides on nontarget plants and animals is a potential risk (CRC 2003).

How does it spread?

Vegetative spread occurs when any part of the stem that includes a node breaks away from the main plant, e.g., in fast flowing water. When the stem fragment settles on the stream bed it sends out fine roots from the node, and can grow into an entire new plant. Detached leaves also have the ability to reproduce from leaf veins. Stem fragments can also be accidentally spread by transport of machinery, e.g., boats, trailers, lawnmowers or in animals' hooves Seeds are also responsible for local and long distance dispersal. Butterfly enthusiasts are known to favour this plant due to its fragrant flowers, so it is attractive to butterflies. Plant swapping and trading between butterfly enthusiasts is a likely pathway for secondary invasions within Australia (GISD 2006).

Recent research has shown that seed production in infestations near Brisbane are extremely low, less then 1% of its potential, which indicates that spread of Senegal Tea Plant by seed is not very important there (CRC 2003).

What is its history in Australia?

Senegal Tea Plant was introduced to Australia by the aquarium trade, possibly in 1974. It is mainly spread by the careless disposal of aquarium plants or deliberate cultivation for sale (CRC 2003).

How To Manage It?

Best practice management

Because there are relatively few Senegal Tea Plant infestations, and it can potentially be eradicated before it becomes established, any new outbreaks should be reported immediately to your state or territory weed management agency or local council. Do not try to control Senegal Tea Plant without their expert assistance. Control effort that is poorly performed or not followed up can actually help spread the weed and worsen the problem (CRC 2003).

Chemical control: Senegal Tea Plant is very hard to kill and herbicides effective on similar plants kill only the upper parts of the plant. Any material that is below the water line is not killed, and can regrow. Long-term experience with glyphosate has shown it is not an effective eradication tool. Some of the problems are that it is non-selective and also kills native species such as swamp grasses and sedges. It also has no residual effect which means it creates a gap which is flooded by light, an ideal seedbed for Senegal Tea Plant to re-grown. In addition, the plant fragments after toxin application, resulting in leaf abscission and propagule formation reused (CRC 2003; GISD 2006).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au.

Non-chemical control: Physical control: Hand pulling often results in regeneration and further spread, but can be effective on small infestations. Mechanical control: Physical methods that include the use of heavy machinery combined with chemicals has been found to be effective. Infestations are sprayed with a herbicide to reduce the risk of spreading plant parts. Then 7-10 days later all silt and plant material up to a depth of 1 m is removed by heavy machinery. Depending on local weather conditions, all plant material is dead after about a month and the silt and soil can be reused (CRC 2003; GISD 2006).

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Senegal Tea Plant is a perennial that flowers in late spring or early summer and continues to late autumn. Seed formation occurs about one month after flowering. Plants become dormant during winter and new growth reshoots from the crown and nodes during the following spring. Most seeds germinate in spring, although some germination may continue into summer. Seedling growth is rapid and plants quickly reach the surface if submerged in shallow water. It is a perennial that lives for at least several years (CRC 2003).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, TAS, VIC, WA

What areas within states and territories is it found?

The first naturalised specimen is believed to have been collected in 1980 from Oxley Island in the Manning River near Taree, New South Wales. Additional infestations are known to exist at four locations from Taree in the north to Dapto in the south of New South Wales.

An infestation has also been discovered in Tasmania (Csurhes & Edwards 1998), and recently from Perth and South Cranbourne in Victoria (CRC 2004).

Queensland recorded the first naturalised plants in 1995 at Redland Bay and since then small infestations have been found near Brisbane and in Cedar Creek at Mt Tamborine (Csurhes & Edwards 1998).

Where does it originate?

Senegal Tea Plant is a native of tropical and subtropical regions of the Americas, from Mexico to Argentina, where it has also been recorded as a weed. New Zealand and India are other countries where it has become weedy (CRC 2003).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

ACT, NSW, QLD, SA, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

YES

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Gymnocoronis spilanthoides

Other scientific names (synonyms)?

Alomia spilanthoides D.Don ex Hook. & Arn.

Does it have other known common name(s)?

Temple Plant, Senegal Tea, Spade Leaf Plant