By Pat Dray
The Garden Spot
Pat Dray
Most gardeners think of plants that are grown from a lumpy looking underground clump as bulbs, mainly spring bloomers that we plant in the fall like tulips and daffodils. When a friend gave me canna lily “bulbs,” I had a lot to learn about these sunny border queens.
Canna lilies (genus Canna) aren’t lilies, but they’ve earned their name because of their flamboyant flowers and lush, tropical foliage. Nor are they bulbs, but rhizomes.
Rhizomes are those lumpy looking stem-like structures that grow horizontally, forming roots from the bottom and sending shoots upwards. They often appear as nothing more than roots and are basically underground storage systems for the plant. The buds form at different parts along the rhizome, not just the tip as would be the case with a bulb. One thing I found interesting is that because they aren’t bulbs, my favorite bulb wholesalers, such as Colorblends in Bridgeport, don’t carry them. But no worries: some of the big box store have cannas available in containers which you can either plant in the ground or leave in the container for the growing season.
Their flowers come in a variety of colors, usually in the red and orange range. They have large green and/or red leaves.
Cannas are native to tropical and subtropical regions of the Americas and were grown by indigenous peoples who used its starchy rhizomes as food and medicine. When Spanish explorers brought cannas to Europe in the 16th century, they quickly became all the rage by the mid-1800s in Victorian gardens for their exotic appearance. They were so popular that massive displays of cannas were a centerpiece at the 1893 Chicago World’s Fair.
Here in the Northeast, canna bulbs would be planted in late April through early June after the danger of the last frost and when nighttime temperatures stay above 50 degrees. I know this was quite a challenge this year as we didn’t have consistent 50-degree nights until late May.
Plant them in a sunny location, as they do best with six to eight hours of direct sunlight daily. They should be planted between 5-8 inches deep in a rich, well-draining soil with a neutral to slightly acidic pH (6-7). Do you remember soil pH from the previous Garden Spot? If you already had your soil tested, you would know if you need to add any amendments. You should also feed them mid-summer with a balanced fertilizer such as a 10-10-10. Since these are tropical plants, the soil should be kept moist and not allowed to dry out.
Here in Connecticut, you’ll need to dig up rhizomes after the first frost. Let them dry out for a few days, then store them in peat moss or vermiculite in a cool, dry place (40–55° Fahrenheit) until next spring. Your cannas should be striking in the back of a sunny border – remember some of them get as tall as five feet – so definitely worth the extra step.