Canna (aquatic group)

Common Name: canna 
Type: Herbaceous perennial
Family: Cannaceae
Zone: 7 to 10
Height: 2.00 to 6.00 feet
Spread: 2.00 to 3.00 feet
Bloom Time: July to September
Bloom Description: Red, salmon pink, yellow, burnt orange
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Medium
Suggested Use: Annual, Water Plant, Rain Garden
Flower: Showy
Attracts: Hummingbirds
Tolerate: Wet Soil

Culture

Best grown in moist, organically rich, well-drained soils in full sun. Plant rhizomes 4-6” deep and 18-24” apart in spring after threat of frost has passed. Remove entire flowering stems immediately after bloom. Rhizomes are reliably hardy in USDA Zones 7-10, but can be lifted in fall for overwintering in colder climates. In fall, cut plants to the ground after first frost and lift rhizome clumps for winter storage in a dry medium (peat or vermiculite) in a cool dry location than does not fall below 40°F. Rhizomes may be occasionally sprayed with water in winter to make sure they do not become so dry that root shriveling would occur. Container grown plants can be stored in their containers in winter. Propagate by division in spring before replanting outdoors.

Noteworthy Characteristics

Canna is a genus of around 10 species of rhizomatous, tropical and subtropical, herbaceous perennials that produce flower spikes from summer into early fall atop erect stems sheathed in large paddle-shaped leaves. Cultivars are available with colorful foliage and flowers in a range of warm colors including red, orange, yellow, pink, and creamy white. The flowers are attractive to hummingbirds.

Genus name comes from the Greek word kanna meaning "reed".

Aquatic cannas are hybrid cultivars that tolerate being grown in shallow water. Most are crosses between Canna glauca and several terrestrial species. Canna glauca is a water canna is native to South America and is noted for its blue-green foliage and its ability to grow well in shallow water. Species plants grow 4-6’ tall and feature narrow, blue-green leaves (to 18” long) and small pale yellow flowers.

Problems

Rhizomes may rot in poorly drained wet soils. Leaf spots, rust and bacterial blight may occur. Watch for aster yellows. Japanese beetles, caterpillars, leaf rollers, slugs and snails may chew on the foliage.

Uses

Group or mass in beds or borders. Effective planted with both annuals and perennials. Foundations. Large containers. Leaves are particularly impressive when backlit by sun.