Canna x generalis

Garden Canna is a herbaceous perennial in the Cannaceae family native to the tropical and subtropical regions of North and South America and India but has been widely cultivated. It is most likely the hybrid of Canna indica and Canna glauca or Canna iridiflora. Currently, all Canna hybrids are included under the scientific name of Canna x generalis. The genus name, Canna, is from the Greek word "Kanna," which means reed-like. The plants are very large and grow up to 6 feet tall. They will attract attention to any garden whether planted as an accent or in a mass planting. They have large colorful flowers and tropical appearing foliage. The foliage and flower color vary depending on the cultivar.

Garden Canna prefers sunlight to light shade, soils with high organic matter, in a variety of soils, clay, loam acidic and slightly alkaline. They can grow in shade but will not flower well.  They grow best in moist, well-drained soils, but they can tolerate some standing water or drought once they are established. They have a high heat tolerance, but they are prone to wind damage. In warmer zones, the rhizomes may be left in the soil to over winter.  After the first frost, cut the foliage down to the ground and cover with available mulch.  In colder zones, dig up the rhizomes and bring inside and store them in peat or vermiculite in a cool dry space with temperatures between 45 - 50 degrees.  The rhizomes should be planted after the last spring frost. It is best to plant the rhizomes at least 5 inches deep and 12 inches apart.  Spent flowers should be removed to encourage continued flowering through the summer months. The plant may be propagated by seeds, rhizomes, and division. 

Their striking and brightly colored flowers make them an excellent choice for a border grouping, and their tropical feel works well in pool-side landscaping.  

Insects, Diseases, and Other Plant Problems:  Japanese beetles may feed on the young leaves and flower buds. Aster yellows cause dull yellowing of the leaves that eventually turn brown. The disease is spread by aphids. Slugs and snails may also chew on the leaves. Bud rot causes spots on the unfolding leaves running together along the leaf veins.  They start as white but eventually turn black.  Infected buds turn black before they open.  The plant is susceptible to leaf-rolling caterpillars. Canna mosaic virus causes pale yellow stripes on the leaves. Leaf spot, rust, and bacterial blight may be also be found. The rhizomes will rot in poorly drained soils. 

VIDEO Created by Elisabeth Meyer for "Edibles, Bulbs, and Houseplants" a plant identification course developed in partnership with Longwood Gardens.   

More information on Canna.