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.
Growth form (weed type/habit)
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.