How to Care for Giant Cannas

Wait until there is no chance of frost in your area to prepare the planting bed for the giant canna rhizomes. Choose a sunny location with well-drained soil and wind protection.

Loosen the soil to a depth of more than 12 inches. Incorporate 2 to 4 inches of compost, aged manure or other organic matter into the planting bed.

Dig a hole 4 to 6 inches deep for each giant canna. Space the holes at least 2 feet apart. Place the rhizome in the hole horizontally, with the eyes facing up, then cover it with soil.

Soak the entire planting area with water to firm the soil around the giant canna rhizomes. Continue to supply at least 1 inch of water weekly from spring to fall, using supplemental watering if rainfall is less.

Cover the area around the giant cannas with a 2- to 4-inch layer of mulch to preserve moisture. Cannas thrive in moist soil, and the mulch prevents weeds from emerging.

Apply a balanced fertilizer once the giant cannas appear. Follow the directions on the label and reapply monthly throughout the entire growing season.

Remove any faded flowers to encourage additional blossoming throughout the growing season. Allow the plant's foliage to die back completely in the fall before cutting the giant cannas back to 6 inches.

Dig the canna rhizomes up in areas outside of the recommended growing zones. Store them indoors for the winter and then replant them when the soil warms up in the spring. You can also cover the area with a thick layer of mulch.