How Long Does It Take for Cannas to Grow?

Canna Growth

• Canna flowers grow from fleshy underground roots that store nutrition and information from year to year. In areas that experience mild frosts, canna flowers and foliage die back to the ground in fall and return in spring. In frost-free areas, cannas grow year-round continuously, sending up new leaf stalks and flower shoots as the old ones die back. Cannas grow in U.S. Department of Agriculture plant hardiness zones 7 through 10.

Planting Canna Rhizomes

• Plant canna rhizomes outside two weeks before the last frost date in your area. The soil protects canna tubers from mild frosts. As spring progresses, the roots send up new shoots. The leaf shoots develop in spring and the flowers bloom through summer and into early fall. As the flowers fade, remove the flower stalks 1 inch above the soil line. According to the University of Florida IFAS Extension, cutting back the flower heads encourages prolonged blooming. In frost-free climates, keep the spent flower heads cut back for year-round flowers.

Growing Cannas From Seed

• The seeds require two to three weeks to germinate and emerge from the soil. Soak the seeds in lukewarm water for 24 hours before planting to soften the hard seed coat. Plant the seeds in damp peat moss and keep them at 75 degrees Fahrenheit during germination. Start seeds in late winter and plant out after the last frost date. Cannas, planted from seed in late winter, flower during the summer of that year.

Cultivating Cannas

• Cannas like a spot in full sun but tolerate partial sun. Select a spot that has sandy or loamy soil and good drainage. Cannas thrive with consistent moisture; water once or twice a week during dry weather to keep the soil damp. Fertilize cannas using a balanced fertilizer. In regions outside hardiness zones 7 to 10, dig cannas in the fall and store in a cool, dry place until spring. Replant two weeks before the last frost date.