Cannas have two givens in this world: They are typically Southern and they are much maligned.
There’s a reason for both. There are 20 or more Canna species in the world, all from tropical regions. Therefore, they can’t tolerate much cold. And though they are long-lived perennials in the South, are only adapted as showy annuals in the North. This actually makes them more desirable in the North. Folks always like plants that don’t grow in their area. If you have to work much harder for something, the value always goes up. Up there, they groom the foliage and dead head the flowers throughout the season, followed by digging and storing them for the winter. In the South, they thrive with no care in ditches and in other areas, which naturally makes their “value” decrease.
This is just part of the reason for their being maligned. They are also unfortunately often plagued by canna leaf rollers. It’s only a plague, however, if you aren’t a nature lover and a butterfly enthusiast. For the canna leaf roller is the larva of the little Brazilian skipper butterfly, also from the tropics. Skippers are named for their quick, jumpy flight pattern. They reproduce and follow annual canna plantings up through the U.S. during the summer and return each year as “snowbirds” to spend the winter in South Texas, southern Florida and the tropics. If you aren’t fond of home butterfly production, they are easily controlled with the organic, biological insecticide, Bacillus thuringiensis (Bt) sold as Dipel, Thuricide or worm killer.
Wild cannas tend to be tall plants with small flowers and produce small, round, shot-like seed. Cannas occur in a wide range of colors, from yellow, orange and reds to pinks and creams. Many have bicolor, or spotted, flowers. They also can be green leafed, red leafed or variegated. Those with variegated foliage have been all the rage over the past decade. Many use the showy foliage in floral design. Over the years, cannas were bred to be dwarf plants with larger and larger showy flowers and produce no seed. They were very popular as bedding plants during the Victorian period.
Though they aren’t in vogue with upscale gardeners, I’ll have to admit that I’ve always been a bit fond of them. Many “snooty” gardeners consider them coarse and vulgar. My country people liked them because they were easy to grow and came back every year.
Cannas perform best with rich, moist soil and plenty of sunlight. If the flowers look bad on your cannas, cut the stalks and they’ll make new ones. If the foliage looks bad, cut the whole plant down, scatter a bit of lawn or garden fertilizer around it, add water and it will come back looking good again.
Greg Grant is the Smith County horticulturist for the Texas A&M AgriLife Extension Service. He is co-author of “Heirloom Gardening in the South” and “The Rose Rustlers.” You can read his “Greg’s Ramblings” blog at arborgate.com, his “In Greg’s Garden” in each issue of Texas Gardener magazine (texasgardener.com) or follow him on Facebook at “Greg Grant Gardens.” More research-based gardening information from the Texas A&M AgriLife Extension Service can be found at aggie-horticulture.tamu.edu and plantanswers.com.