The tropical zone contains plants from the garden’s evolution and useful plants collections, including displays of floral diversity, adaptation to the environment and Chinese medicinal herbs.
A raised tropical pool is the centrepiece of this zone and is home to many tropical aquatic plants including water hyacinth, Eichhornia crassipes, water lettuce Psitia stratiotes with the corner planters planted with marginal plants: papyrus Cyperus papyrus, powdery alligator flag, Thalia dealbata and the blue taro, Xathosoma violaceum. Here two plants of the giant Amazon water lily Victoria cruziana and sometimes Victoria amazonica produce huge leaves and large beetle pollinated night blooming flowers. Surrounding these are a collection of sacred lotus, Nelumbo nucifera from China representing the most comprehensive collection of traditional Chinese sacred lotus in the United Kingdom, which flower throughout the summer when many different colour forms can be seen.
Tropical economic ‘crop’ plants including, cocoa Theobroma cacao, sugar cane, Saccharum officinarum and banana Musa acuminata ‘Dwarf Cavendish’ are grown direct in a narrow border. Potted plants of dwarf pineapple, Ananas comosus ‘Nanus’, vanilla, Vanilla planifolia, ginger, Zingiber officinale and turmeric Curcuma longa are grown on the benches.