The leaves of Senecio pleistocephalus are alternate, glossy, fleshy and leathery. The leaf shape is elliptic with sparsely toothed margins.

The strong, branched stems reach 2 m in length. They are often notably straight and sturdy as in this picture, pale green to purplish in colour when young. Both leaves and stems are hairless. Old stems are whitish and slightly rough in surface texture.

The plant is listed by Smith, et al (1997) as a succulent.