The largest of the two species of the genus Canna in the display is Canna iridiflora and differs by having pendant flowers. This species originates from Peru, Colombia and Costa Rica. It has the ability to grow to double the height of Canna indica, at 5m! It is sometimes grown outside in the U.K. during the summer months.
Canna iridiflora
This species was in cultivation in the U.K. by 1816 and is listed in Johnson’s Gardeners’ Dictionary of 1856. It was very popular in the exotic summer plantings of the Victorian era but went out of fashion due to war time lack of fuel to warm glasshouses in the winter. In recent years it has again become popular for its exotic appearance that combined large leaves and bright nodding flowers. It likes plenty of nutrients and appreciates regular addition of fertilizer.