Alluaudia procera, or Madagascar ocotillo from Madagascar is a drought tolerant succulent with a variable growth habit. One of the more unusual succulents, this is a relatively easy care plant and it grows well in cooler climates.
Alluaudia procera is a spiny and scarcely branched or occasionally columnar, small succulent tree with a very upright habit that looks a lot like a "crown of thorns". The plant can grow rather tall, 1,5-3 m high indoors and up to 18 m tall in its native haunts (but cultivated plant rarely surpass the 8 m of height). The leaves are small, oval or rounded, green succulent that bud right off the trunk, 1 to 5 cm (or more) long. The leaves clothe the stems during the warm wet season, but will often drop during any lengthy dry periods or (usually in cultivation) with the onset of winter. The flowers are yellowish white in crowded clusters at the end of the branches. Flowers will be produced in mature specimens taller than 3 m on separate male and female plants.