How do I prepare my Canna for winter storage?
Success in overwintering your Canna’s tender rhizomes, requires removing them from their pot. It is best to wait for a light frost, before digging them up. The guide below will help protect your tender plant for next years’ show.
In the fall, dig rhizomes after the leaves have yellowed, died back or have been killed by a light frost, but before the ground freezes. Leaving your cannas till after a light freeze, not a hard freeze, provides the longest possible growing season so the plant can store food taken from its leaves for next year's growth. Then cut back dead foliage to 2 inches. Carefully dig cannas with a shovel or spade, or carefully with a garden fork. Cut all around the clump. Lift rhizome clumps out of the ground and shake off any excess soil. Rinse the rhizomes with water to remove any dirt. Rhizomes should be air dried in a well ventilated area at 70 to 80 degrees F. Cannas need one week, more or less to dry. Once dried remove any foliage that remains. Store in a cool, dark and humid (about 40-50%) place with good ventilation; place in a cardboard box cushioned with shredded paper or store the dried bulbs between 2-3" layers of peat moss, sand, vermiculite, sawdust, wood shavings or coir (shredded coconut husk fiber). Do not pack the bulbs in air-tight containers; that could cause moisture build up and promote decay. Make sure the individual bulbs are not touching, otherwise if one starts to rot, the decay can spread to the others. The bulbs should be held in a location with temperatures around 40ºF. Do not store the rhizomes in an attic or garage that may freeze. Check throughout the winter and discard shriveled, diseased, or insect infested rhizomes. If they have dehydrated – they have shrunk and are wrinkled – moisten the layering medium a little (such as with a spray bottle) and re-pack them. If they are very moist remove from the packing material and air dry for a few days before repacking in dry material. Wait until spring to divide, breaking apart, making sure there are at least 3 eyes per division for planting.
Courtesy of the NYBG Plant Information Service