The Canna: a large tropical herbaceous perennial with a rhizomatous rootstock and flowers in red, yellow orange and pink shades, which are attractive to bees.
written by
Hilary Collins BSc. (Hons)hort., M.C.I.Hort.
Originally published: 2013 in The Edge
Spring flowers are easy; take a handful of white Spirea, a few cherry trees, throw in some early perennials, a thousand bulbs and your display is complete. But without careful planning, by July you may be left with bland borders and frazzled foliage. Seemingly every year, our poor garden plants are put under trial with unpredictable, ever-more-extreme English weather: Borders are often drowned by endless rain, abruptly followed by interminable drought.
Stately homes, parks and gardens have exploited the benefits of the Canna for centuries and now, with 1000’s of annual visitors flocking to see the gardens of England, large borders must be filled with vibrant colour until the close of the season. Summer plants need stamina and whilst dahlias revel in full sun, the Canna gives of its best from July till first frost, no matter what is thrown at it, even dry shade.
You would think these exotic beauties would demand deep rich ground and oodles of water.
Not so!
Water cannas are for growing in bog gardens, but the floral and foliage types are great for borders and patio pots. A good plant for global warming, cannas are very adaptable, with the ability to hold their own, when all around is drooping in drought; but given moist fertile soil, cannas go mad and produce tall, fat stems.
Strong, firey colours of red, yellow, apricot/orange and hot pinks look great in bright light, but I have found in my own garden that strong sun bleaches the flowers and the foliage, especially of striped foliage of C. Pretoria and dark purple varieties, becomes pale.
Cannas do best in semi-shade and will illuminate dull, garden corners.
Originating exclusively in the Americas, cannas are closely related to the families of culinary Ginger (Zingiberaceae), Banana (Musaceae) and Bird of Paradise (Streliziaceae). Once simply a wild tropical plant grown if anything for animal fodder, the canna was taken to Europe in the 16th century, where extensive breeding was carried out and on to England as a garden foliage plant.
Unsurprisingly, the Victorians became involved and grew large numbers of these plants for spectacular flower and foliage displays.
The large, lush leaves and beautiful blooms of the modern day cultivars are deeply attractive and easily cultivated; requiring only 6-8 hours sunlight in summer and frost free protection in winter. They are now grown all over the world: even in the Arctic Circle, with its short growing season.
I have collected cannas over many years, but became disillusioned in the mid noughties. Initially unaware of the Canna virus, I gave up eventually, as my plants failed to thrive.
Later, I was disappointed to learn that most of the Canna world was, back then (and still is) contaminated with virus, which manifests itself as yellow streaks through the foliage; plants contort, turn brown and wither. There is a distinct lack of willpower and effort being put into cleaning up the industry, particularly on the part of the big European producers, supplying the major retail outlets of this country.
However, at the RHS Malvern Spring garden show, my fascination for these exuberant, bold architectural plants with their tropical foliage and exotic flowers was rekindled, whilst visiting the stand of Keith Hayward. Keith, with his wife Christine, holds the National Collection, and together they run Hart Cannas.
I was very encouraged to hear from Keith about their concerted effort to source, grow and supply only disease free tubers. Any infected plants are instantly destroyed. You can read about Keith’s crusade to clean up cannas at http://cannanews.blogspot.co.uk/2008/01/thoughts-on-virus-from-hart-canna.html
Left to right: dark purple Canna indica 'Russian Red', pink flowers of Canna 'Shenandoah', and the lush leaves of Canna musifolia.
Which varieties to choose?
There used to be 100’s of varieties available but 2 World Wars depleted many collections. Of late, Cannas are gaining in popularity, as gardeners identify with this easy, drought resistant plant
A few of my favourites:
C. ‘Pretoria’ RHS AGM (aka ‘Bengal Tiger’) herringbone stripes of cream on green with large apricot orange blooms. One of the best ‘classic’ canna varieties
C. ‘Ambassador’: large, nicely shaped creamy white flowers, against deep green foliage. Good for gloomy corners
C.‘Ehemannii’ AGM: this hybrid of C. iridiflora from the cloud mountains of Peru is a most beautiful, large, dramatic plant with nodding trusses of cerise flowers
C.‘Shenandoah’: an oldy, but good. ‘Barbara Cartland’ Shocking pink flowers set against perfect bronze foliage.
Looking good together: C. ‘Carnival’ tangerine suffused ‘n’ spotted on warm yellow and C. ‘Calimero’ strong vermilion overlays warm yellow
C.‘Wyoming’ AGM: 2m tall dark bronze foliage as a background to tangerine blooms is a stunning all-time favourite.
Getting ‘Jungle Fever’
I love the mad C. ‘Musifolia Grande’. Over 2m tall with emerald green foliage, red veins, leaf edge and stems. Small red flowers may occasionally be produced at the end of the season, but this canna is most spectacular when leaves are backlit by a setting sun. Plant with Ricinus carmencita, Bamboos or Miscanthus and you would think you were in the jungle.
Also, the even taller C. ‘Stuttgart’: at nearly 3m, the glaucous leaves splashed with white will brighten the gloomiest garden recess. C. ‘Russian Red’ AGM: Keith’s own selection is a mouth-watering burgundy beauty, with orange flowers. It is best grown in front of a light green shrub to display the dramatic red-bronze foliage.
So the message is clear: purchase healthy Canna rhizomes and plants from a reliable supplier and enjoy vibrant colour all summer long.
Visit: www.hartcanna.co.uk to view the Haywards extensive disease-free selection.