Lobelia cardinalis - Potted Plant P108 - Buy 2 GET 1 FREE All our plants pass USDA requirement Imported from the Rain Forrest in Thailand - USDA Certified Lobelia cardinalisgrows wild in Northern America. In the nursery this plant is cultivated in marshy conditions, forming dark-green leaves which are purple underneath. In aquariums the leaves turn a beautiful shade of light-green, with stems 10-30 cm tall and 5-10 cm wide. It needs intensive light to thrive. idely used in Dutch aquariums in so-called "plant streets''. In open aquariums it grows above the water surface, where it forms very beautiful scarlet flowers and the leaves regain their color. Can be used in garden ponds.