The Weather Channel is predicting freezing temperatures this Friday night. Be sure to get outside while the weather is decent if you would like to save these tropical plants from the frigid temperatures that lie ahead.
The most important thing to do when digging up rhizomes or any tender bulb is to be careful not to wound these fleshy underground structures. Wounds and bruises serve as entry points for diseases which can cause rotting and loss in storage.
I start by cutting back the foliage in order to see the ground near the base of the plant (Photo 2). I dig back several inches away from the base and loosen the soil using a spade shovel (Photo 3). I remove the large clump of multiple rhizomes from the ground (Photo 4). The rhizomes multiply underground throughout the growing season, so even though you may have only planted 3 to 5 rhizomes this past summer, you may have well over ten by now. I carefully separate the clumps and remove most of the soil using my hands (Photo 5). Then, I lay them out and wrap each individual rhizome in newspaper (Photos 6). Next, I layer them in a large tote with the lid off (Photo 7). This is how they will remain stored in my basement until next spring. I monitor the tote every month to check for rotting pieces and pests.
As you read through the literature available, other sources have varied recommendations for storing methods. One thing for sure is to keep canna rhizomes stored at 35 to 50 degrees Fahrenheit. I have read of people having success in storing them in an unheated garage or shed. Other sources suggest allowing the rhizomes to cure and dry out for 1 to 3 days before storing. Another source recommends removing all of the soil once dried and storing in peat moss or sawdust. Over the past four years, I have had success with these same cannas rhizomes using the simpler method of wrapping in newspaper and storing them in a tote, as described above.
Additionally, I have been successful at storing container grown cannas by bringing in the whole container and storing them in an unheated hallway closet (Photo 8 & 10). I simply cut back the foliage after a light frost and place the container indoors. I let them go dormant until the next spring. Miraculously, late the next spring I see signs of leaf growth and place the containers back outdoors once danger of frost has passed. I have to admit that over the past two years these cannas have multiplied in the containers and leave little to no room for planting other flowers. Now, I simply use this container just for cannas and this year I am attempting to overwinter my purple heart (Setcreasea pallida) houseplant in the same container for a trailing effect.
Don't forget to scratch this task off the list THIS WEEK before the heavy frost rolls into town.
To learn more about storing other types of tender bulbs click here. To watch a short video on ways to insulate your container in attempt to overwinter tender plants click here, then click on "proper drainage" video.
NOTE: There is a glitch in the order of photos. Please be patient as this is corrected.