Canna lilies are tall plants with extensive root systems so they need large, sturdy containers—at least 18 inches in diameter per rhizome—to thrive. It is likely that your medium pot will not be sufficient enough for your plant to reach its full potential, so it would be best to upgrade to a larger container that can both support root system growth and reduce the chance that it will become top heavy and tip over as it matures.
Given that your plant is in the midst of its growing season, you will want to wait until it finishes blooming for the season and its foliage begins to die back before transplanting to a new container. When you do transplant, you will want to use fresh potting mix and follow the planting tips outlined above.
Hi Shirley,
Canna lilies are tall plants with extensive root systems so they need large, sturdy containers—at least 18 inches in diameter per rhizome—to thrive. It is likely that your medium pot will not be sufficient enough for your plant to reach its full potential, so it would be best to upgrade to a larger container that can both support root system growth and reduce the chance that it will become top heavy and tip over as it matures.
Given that your plant is in the midst of its growing season, you will want to wait until it finishes blooming for the season and its foliage begins to die back before transplanting to a new container. When you do transplant, you will want to use fresh potting mix and follow the planting tips outlined above.
Hope this helps!