The secret underground life of Cape Geophytes

Some of the Cape’s most remarkable plants spend much of their lives out of sight. Geophytes are plants with underground storage organs, such as bulbs, corms, rhizomes and tubers, that allow them to store energy and survive periods when conditions above ground are less favourable.

The Cape Floristic Region is exceptionally rich in these plants, with more than 2,100 geophyte species. Their underground structures are far from uniform, and neither are their life cycles. While many species grow during winter and flower in spring, others wait until autumn to emerge and bloom. Some even produce flowers on bare stems, long after their leaves have disappeared.

At the Stellenbosch University Botanical Garden, there are fascinating examples to look out for. In the lowland beds, Babiana fragrans is known for its distinctive scent, reminiscent of Earl Grey tea. Near the Neethling Street entrance, the Overberg Renosterveld beds are home to geophytic Pelargonium species belonging to the subgenus Horaea. Unlike the familiar garden pelargoniums, these unusual plants have underground storage organs and can flower after their leaves have died back.

These adaptations are not simply ways of surviving. Underground storage allows plants to conserve resources between growing seasons and offers some protection from fires. Different flowering times also mean that geophytes can take advantage of particular environmental conditions for growth, pollination and seed production.

The next time you visit the Garden, stop by the bulb benches opposite the Botanical Gift Shop. Look beyond the flowers and consider what lies beneath them. Those seemingly modest underground structures hold the resources that allow these plants to flourish, season after season.