Gin and Tonic Lobelia
Remarkably similar to the Puya of the Andes in South America or Echium wildpretii from the island of Tenerife, albeit totally unrelated, this giant rosette plant is living proof of the concept that similar habitats produce similar looking plants as they select for the same succesful growth patterns. Lobelia gregoriana subsp. gregoriana is native to wetter spots in the alpine zone of Mount Kenya between 3300 and 4600 m, where the extreme climate is usually clear and cold in the mornings with intense sunshine, cloudy or foggy in the afternoons and clear and frosty at night. Daytime temperatures are usually only a few degrees above freezing. Lobelia gregoriana forms a short-trunked, compact rosette of broad, stiff leaves with a reddish hue from a branching underground rhizome. When mature, which in its cold habitat can take decades, a rosette forms an impressive, large, terminal, conelike inflorescence with recurved bracts that is pollinated by birds. Similar to many bromeliads, the leaf rosette holds a reservoir of water among the tightly fitted leaves, which is key to it survival in this unhospitable habitat. This reservoir freezes at night, a process that produces just enough warmth to keep the core of the plant alive until the morning sun thaws the ice. The British must have coined the common name 'Gin and Tonic Lobelia' for the ice cubes produced this way in the plants leaf rosette. In cultivation, the giant Lobelia are rare and best suited to high mountain or highly oceanic climates without extremes of heat or cold. Lobelia gregoriana is successfully grown in southern New Zealand.