Acanthus montanus

Acanthus montanus, also known as bear's breech or mountain thistle and in Igbo; ogwu_ahga (in Agbani, Enugu State Nigeria) is a species of flowering plant in the genus Acanthus. It is native to tropical Africa, growing in wet and shady places like stream borders in Sierra Leone in West Africa and from Benin to Chad, Zambia, and Angola in central Africa.

It is a thinly branched perennial with basal clusters of oblong to lance-shaped glossy, dark green leaves reaching up to 12 in long. The leaves have silver marks, wavy margins and thorns. It reaches up to 6 ft tall and about 24 in wide. Spikes of pale pink flowers appear summer to fall.

In cultivation it prefers shady situations and occasional deep watering, but tolerates sunny, dry situations too. Its aggressive roots make this plant well suited to slopes.