Tropical canna plants are perennial in their native climate but are grown as annuals in most areas of the United States. Plant canna in borders or in beds to add more color to your landscaping. They have ornamental leaves that range in color from green to ruby, and some varieties have stripes or other variegation. The large, brightly colored flowers add additional interest to the plants. Proper fertilization ensures the canna continue to produce healthy foliage and bloom profusely throughout the warm summer months.
Prepare beds prior to planting in spring. Lay a 2-inch layer of fully composted manure over the bed, and work it to a 12-inch depth with a tiller to provide soil nutrition throughout the growing period.
Apply a third cup of nitrogen-rich fertilizer, such as a 12-4-8 formula, to each planting hole prior to sowing the canna rhizomes. Mix the fertilizer with the soil in the hole. This encourages the rhizomes to quickly take root and grow quickly.
Fertilize canna once monthly with a 5-percent nitrogen fertilizer. Apply 2 pounds of fertilizer per every 100 square feet of canna bed. Till it in between plants.
Fertilize container-grown canna with the same fertilizer types as bedding plants, but use a quarter of the amount of fertilizer per container, and apply it once every two weeks. Fertilizer nutrients wash out of container plants more quickly than they do from garden beds.