Water Canna Canna glauca

Canna Glauca is a species of the Canna genus, a family of large tropical plants that produce gladiolus-like flower spikes in summer. The flowers of Canna Glauca can be red, salmon pink, yellow, or burnt orange and sit atop tall erect stems that are sheathed in large paddle-shaped leaves. The foliage is also very colorful and allows the plant to retain ornamental interest when not in flower. Because the leaves are so large, you should avoid placing the plant where it would be subject to high winds. Canna Glauca, like the Canna genus, is a herbaceous perennial that grows best in moist, organically rich, well-drained soils in full sun or partial shade (it cannot grow in full shade).

To propagate the plant, remove the flowering stems after blooms have passed and, in the fall after the first frost, cut the plant back to the ground. You can leave the rhizomes, or bulbs, in the ground if your winters are temperate (usual in USDA zones 7 through 10); however, if winters include freezes, treat the plant as an annual and dig up the rhizomes in fall and store them in a dry medium such as peat or vermiculite in a cool dry location that does not get below 40 degrees F over the winter. In the spring, after the last frost, plant the rhizome 4 to 6 inches deep. If the plant has been grown in a container, you can submerge the container in ponds or water gardens with the crowns under no more than 8” of water. Lift the containers in fall, cut back the plant tops and overwinter the containers in cool, dry, frost-free locations until spring.

Canna do well in water and can be grown in up to 6 inches of water during the summer. If this is your strategy, you should gradually introduce the plant to aquatic life. It also does best in full sun and cannot grow in full shade.

Diseases, Insects, and Other Plant Problems:

Keep in mind that rhizomes may rot in poorly drained wet soils and the plants are susceptible to damage from aster yellows. Japanese beetles, caterpillars, slugs and snails that are known to chew on the foliage. 

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

More information on Canna.