My lily seems to be dying! It used to blossom flowers, but then dried up. I keep it indoors next to a window. Outside I watered it twice a day. When I brought it inside, it started dying so I watered it less on my friends advice – every few days. Now it is dying. How often should it be watered? At this point, do I need to replace the soil and prune the roots?
Thanks for your question. It is very common for any plant that has been grown outdoors in the summer to experience temporary setback when brought indoors for the winter. Your canna lily did not start to die when you brought it inside. Rather, what you observed was the plant’s response to the sudden change in light exposure and other environmental conditions from being moved inside. If you also reduced the frequency of watering, the soil may have dried out, which may have signaled the plant to go into dormancy (the lily grows from a rhizome, which can survive periods of drought that would occur naturally in the wild).
The best approach would be to place the canna lily in the sunniest indoor location you can provide, and increase the frequency of watering to maintain consistent soil moisture. Fertilize lightly using an all-purpose fertilizer diluted to about half the recommended amount according to package instructions. The canna lily should continue to grow and put out new healthy leaves, and may even bloom for you. You can repot into a larger container, with new soil, when it’s time to put it back outside next summer. There is no need to prune any roots. The longer the canna lily grows, the bigger the rhizome will become, and the larger the plant will be. Larger plant = more flowers!
If you are unable to keep your canna lily indoors in a location that receives at least several hours of direct sun each day, growth will remain slow. You can let it grow anyway, but it will not require as much water and should only be fertilized sparingly, if at all. Alternatively, you may want to consider letting it go dormant until next year. In that case, stop watering the plant altogether and allow the foliage to die completely, then cut the dead foliage back. You can leave the rhizome in the soil and store the entire pot in a cool location around 5-10 degrees celsius. In spring or summer, return the pot to a warm, sunny location – ideally 20 degrees celsius or higher – and resume watering, first lightly until new growth emerges, then more regularly to keep the soil consistently moist.
For more information about canna lilies, please click here.