The Banana Canna is a striking plant known for its substantial foliage and vivid blooms, bringing a tropical presence to any garden. Its robust growth and distinctive appearance make it a popular choice for creating a lush, exotic atmosphere.
Key Characteristics of Banana Canna
Banana Canna’s physical attributes define its tropical aesthetic. Its most distinctive feature is the expansive, paddle-shaped leaves, which can reach lengths of up to 3 feet (90 cm) and resemble those of a banana tree, hence its common name. These large leaves typically display shades of green, often featuring a bronze flush, maroon edges, or prominent red veining. The plant itself can attain an impressive mature height, ranging from 8 to 15 feet (2.4 to 4.7 meters), establishing a significant vertical element in the landscape.
While primarily cultivated for its bold foliage, Banana Canna also produces flowers, though they are often less conspicuous than those of other canna varieties. These small, often orange-red blooms with slender petals emerge atop tall stalks from mid-summer until the first frost. In some cultivars, flowering may be infrequent, particularly in cooler climates. Its architectural form and large, colorful leaves create a strong visual impact, making it a focal point in garden designs.
Planting and Growing Banana Canna
Planting Banana Canna requires selecting an appropriate site and preparing the soil. These plants thrive in full sun exposure, which promotes their best performance and bloom production. While they can tolerate partial shade in hotter climates, ample sunlight promotes stronger growth. The soil should be well-draining, organically rich, and consistently moist, ideally with a pH level between 6.0 and 7.5. Amending the soil with compost or well-rotted manure can enhance drainage and nutrient content.
Planting Banana Canna rhizomes should occur in spring, after all danger of frost has passed and the soil temperature has warmed to at least 50-65°F (10-18°C). Rhizomes should be placed 4 to 6 inches (10-15 cm) deep in the soil. Spacing is important to accommodate their large size, with recommendations ranging from 18 to 24 inches (45-60 cm) apart for tall varieties, or 2 to 4 feet (60-120 cm) for mature plants. For an earlier display, rhizomes can be started indoors in pots approximately a month before the last expected frost.
Ongoing Care for Banana Canna
Consistent moisture is important for Banana Canna, as these plants are heavy water users, especially during warm summer months. While they appreciate moist conditions and can even grow in wet areas, waterlogged soil should be avoided, particularly in containers, to prevent rhizome rot. Regular watering helps maintain necessary soil moisture. A layer of mulch can also be applied to help retain soil moisture and regulate soil temperature.
Banana Cannas are heavy feeders and benefit from regular fertilization to support their vigorous growth and large foliage. A balanced fertilizer, such as an 8-10-10 NPK ratio, can be applied monthly during the growing season. Slow-release fertilizers or organic amendments like compost can also be incorporated to provide a steady supply of nutrients.
In colder climates (USDA Zones 7 and below), Banana Canna rhizomes typically need to be lifted and stored for the winter. After the first frost, stems should be cut back to the ground. The rhizomes can then be dug up, cleaned, and allowed to dry for a day or two. Storing them in a cool, dry, and dark place, ensuring they do not completely dry out, helps them overwinter successfully.
Common Issues and Solutions
Banana Canna plants can encounter common pests and diseases. Canna leaf rollers are a notable pest, with caterpillars that bind leaves with silk and feed inside, causing holes and ragged edges when leaves unfurl. To manage these pests, hand-picking larvae, applying Bacillus thuringiensis (Bt) products, or using insecticides like spinosad can be effective. Removing and destroying infested plant material at the end of the season can also reduce overwintering pupae. Other common pests include:
Aphids
Slugs
Snails
Japanese beetles
Spider mites
Scale insects
These can cause yellowing leaves or stunted growth.
Canna rust, caused by Puccinia thaliae, appears as yellow to tan pustules on leaves, later turning brown or black. Removing and discarding infected leaves immediately, ensuring good air circulation, and planting in full sun can help prevent its spread. Fungicides, such as copper-based sprays, may be used in severe cases. Other potential diseases include botrytis blight and rhizome rot, often linked to overly wet conditions, and various viruses that can cause leaf streaking, mottling, or stunted growth. For viral infections, removing the entire affected plant is often the only effective solution to prevent further spread. Maintaining proper plant spacing and sanitizing gardening tools also contribute to overall plant health.