Alternative common names:
Purple top (English), blouwaterbossie (Afrikaans).
Tall verbena is a flowering herb with erect stems up to 2m tall which are noticeably square in cross-section and rough. Leaves are stalkless and clasping the stem at the base, thick textured, strongly veined beneath and the margins are sharply toothed. Flowers are purple, appearing in congested terminal spikes.
Where does this species come from?South America.
What is its invasive status in South Africa?NEMBA Category 1b.
Where in South Africa is it a problem?Limpopo, Gauteng, Mpumalanga, North West, Free State, KwaZulu-Natal, Eastern Cape and Western Cape.
How does it spread?The seeds are dispersed by animals, wind and water.
Why is it a problem?
It is poisonous to livestock and invades roadsides, disturbed places, moist areas and grasslands.
What does it look like?
Leaves: Leaves are stalkless and clasping the stem at the base, thick textured, strongly veined beneath and the margins are sharply toothed
Flowers: Flowers are purple, 40mm long, in congested terminal spikes. Flowers appear during summer.
Fruit/seeds: The small fruit separate into four brown, elongated seeds (nuts or mericarps) when mature.
Does the plant have any uses?
Used as am ornamental plant whose flowers are very attractive to butterflies and bees.