I purchased some planters this summer that contained some canna lilies (I think that is what they are called). Please see attached photo. I would like to know the following:
1. When the flowers die, should I deadhead them? I did some but for some I did not deadhead them and the plant bloomed again. Please advise what is best.
2. Do these plants have bulbs? If so, can I store them and plant them in planters for next summer? How should I store them and when should I plant them next year?
3. If these plants do not have bulbs, can I store the plants for next year. If so, how should I do that?
4. Do these plants produce seeds? If so, can I start this plant from seeds, when and how should I do that?
Should the seeds dry on the plant before I pluck them?
Canna lilies are a very dramatic and popular tropical plant for the summer garden or planters. They are easy to care for and their rhizomes can be over-wintered to be enjoyed season after season.
It is always a good idea to deadhead spent flowers and their developing seed pods so that the plant puts more energy into producing more blooms. It is best to wait for all the blooms in the inflorescence (spike or panicle) to expire before cutting off the inflorescence however you can pluck the spent blooms so as to keep the inflorescence looking clean and tidy.
People often refer to Canna lilies as having bulbs however they are actually rhizomes. It is not advisable to over-winter them in their planters as this can cause them to rot. The rhizomes also multiply rapidly and can therefore become choked in their container and produce weaker plants as a result. In the fall, you can dig up the rhizomes (or remove them from the planter) after the frost has killed back the foliage. Cut off the stems to about 2-3 inches from the rhizomes. Separate them and clean off the majority of the dirt. Place them in a dry place (like a garage) to allow them to cure for a couple days. Wrap them loosely in newspaper or place them in a paper bag or cardboard box and store them in a cool and dry location for the winter. Check the rhizomes periodically throughout the winter for any rot and discard any that look suspect. You can start them again indoors in early April to give them a head start for the blooming season. Do not plant more than one rhizome in your planters because again, they multiply rapidly and can be difficult to remove if they become densely packed.
Canna lilies do produce their own seeds. In order to harvest them, the seed pods should be left on the plant until the pods dry and split. The seeds have a hard outer coating that must be pierced and the seeds soaked for a couple days prior to being sown. You can start them indoors in late February using a sterile growing medium. They require lots of sunlight so once they sprout, put them in a warm sunny location. Starting Canna lilies from seed may not produce the same plant as the parent because the parent may have been a hybrid. Therefore, you may be disappointed. It is better to buy the seeds from an online vendor so you know what you’re getting. Of course, the rhizomes produced by the plant would ensure you have the exact same plant the following season. Besides which, the rhizomes multiply readily so you’ll end up having more than you need at the end of the growing season and can share them with friends and family.
A quick search on the Internet will provide you with a plethora of information on the Canna lily. Here’s a link that I found helpful: