This section is from the book "The Florists' Manual", by William Scott. Also available from Amazon: The Florist's Manual.
The canna was of old often called Indian shot, because the seed is excellent as a charge for the shotgun when a stray dog is the game in view.
Few plants have undergone such a change and improvement of late years as the canna. Thirty years ago cannas were grown almost exclusively for their handsome tropical foliage, but since M. Crozy introduced his wonderful hybrids the flower is of more importance than the leaves. Our summers are admirably adapted to the perfect development of the canna and as a decorative plant for our summer gardens it easily Jakes the front rank. Gorgeous beds are seen in the parks, cemeteries, private grounds and even in the humble little garden of the day laborer. In an 8 or 9-inch pot they make grand plants for the decoration of a large conservatory, where you can see the fullest perfection of their grand flowers.
Since the introduction of the Crozy type or, as they are often called, flowering cannas, the old species and types, whose leaves were the attraction and flowers small and few, have sunk into desuetude and are rarely cultivated, because the newer varieties have not only splendid spikes of flowers but all the variety in color of foliage also. There is one of the old type still left that for effect of foliage I have never yet seen equaled by any of the large flowering ones. We call it La Grande Rouge. It grows six feet high in any ordinary soil, has narrow, long, pointed leaves, in color a deep, almost purple, bronze, and very upright habit. For the center of a large bed we don't know its equal.
Our own American florists have raised many grand varieties equal to any of the imported ones. The canna seems well adapted to our climate and environment. In the north in winter, outside the greenhouse, our vegetation is largely hibernating. The somber pines keep green, 'tis true, but we are without the broad-leaved evergreens of the south. Our giants of the forest are bleak and bare and the snowbird flies noiselessly across the waste. Our woods are solemnly still. Our wild plants have scattered their seeds and herbaceous plants are covered with their welcome overcoat of snow. Except for man and his necessities it would be a quiet scene. The bear slumbers in the hollow tree and dreams of honey, the squirrel stops at home and enjoys the fruits of his Irugal care, and the marmot curls up in his deep burrow, but peeps out in early March to see how prospects are, and about the time he takes his first peep is the time to sow canna seed. When spring once comes our vegetation awakens and grows apace. Trees leaf out, it seems, in a night, our woods and fields are clothed with leaf and blossom, and music is everywhere and free to all from the tireless throat of the frog and the sweet call of the meadow lark - which is not a lark at all, but a starling - and it seems to me that the quick and stately growth of the canna is in keeping with all this and is our ideal decorative plant.
Cannas come largely true from seed, and good plants can be raised by sowing in February for the following summer's use. The seed is so hard that it is well not only to soak it in a bag suspended in hot water, which you can renew occasionally, but is all the better if you take each seed, held firmly by a pair of pincers, and slice off a small piece of the hard covering of the seed. Sow in pans in three inches of soil, covering the seed half an inch or more. We place the pans over the hot water pipes, which quickens the growth of the seed. If you have a propagating bed with a good brisk heat in the sand you can sow in drills an inch deep. If you have any seed from your own plants sow as soon as gathered. Canna seed soon loses its vitality. When the plant is three inches high we remove it and start it growing in a pot; but don't throw away the contents of the pan, for there are always more to come and they will likely keep straggling along for months. Grow the seedlings along in a light, warm house and by June 1, which is planting time, they should be in 4-inch pots.
The readiest way and that by which all fine varieties are propagated is by cutting up or division of the root. The old stools that have been stored all winter are divided in March. If the piece of root is three or four inches long, with one good eye or bud, it is large enough to make a fine plant. We place the pieces of root in three or four inches of sand and old hotbed manure in flats about the middle or end of March and place the flats over the pipes where the heat is not too violent. They start to root and grow immediately. Large growers of cannas have cut up the old clump of roots, covered a vacant bench in a warm house with two inche3 of sphagnum moss or cocoanut fiber and then placed the roots on this material, with a sprinkling of the same over the roots. All that are sound will soon make a start and then can be lifted up and potted.
By middle of April you have presumably got rid of your lilies, etc., and can find room to pot off the cannas into 4 and 5-inch pots. They should have a light bench in a light house and no shade, but abundance of water, and by the first of June they will be fine plants, many of them sending up their first spike of flowers.
Any soil that is one-third half rotten manure will do for the cannas. You cannot give them too deep or too rich a soil and they require a great abundance of water. They are usually planted fifteen to eighteen inches apart.
When the foliage is destroyed by frost the tops are cut down to within six inches of the ground and the clump of roots lifted and removed to beneath a dry bench. On the ground beneath a carnation bench is an excellent place, or anywhere the temperature is between 40 and 50 degrees, but it must not be wet or they will start to grow. Neither must there be a drip - the latter is, I know from experience, very bad for them, as the roots will rot. It is better when placing them under the bench to put boards under them, for the moisture of the soil, however dry it may appear, will start them growing. A root house for the purpose, where dahlias would keep, would be the best place, but few of us have that, and beneath the benches is amply good, providing you guard against drip on them.
We always treat the canna as a herbaceous plant, and it is called so by high authorities, but in their tropical home they are by no means herbaceous, spreading and growing and flowering the year round. You can lift, divide and propagate new and rare varieties the year round, and you can lift large clumps before frost has touched them and use them in decorations.
It is difficult to pick out even a dozen varieties, for new sorts are constantly appearing, and what is considered the finest this year may be eclipsed by seedlings of next year. Cannas that do not flower abundantly and hold their flowers well will not do for bedding, and those minus these qualities will soon be lost sight of. Italia and Austria, so beautiful as individual flowers, are useless planted out, as is most likely all that type. Some of the best bedders, if not new, are:
Madame Crozy: Vermilion scarlet, bordered with golden yellow.
Florence Vaughan: Fine yellow, mottled with crimson.
Souvenir de Antoine Crozy: A grand variety; an improvement on Mme. Crozy.
Tarrytown: Rich, bright red; great bloomer.
A Bed of Canna Niagara.
Canna Duke of Marlborough, Edged Buttercup.
Charles Henderson: Deep crimson.
Egandale: Soft red; fine dark foliage.
Chicago: Vermilion scarlet; fine green foliage.
President Cleveland: Orange scarlet; one of the best.
Admiral Avellan: Orange scarlet; fine dark foliage.
Mrs. Kate Gray: Orange scarlet, yellow throat.
President McKinley: Brilliant crimson.
The Express: Fine scarlet; very dwarf.
Buttercup: Pure rich yellow.
Black Beauty: The darkest of all foliage; small flower.
Madame Berat: Deep pink.
Niagara: Dwarf growing, large truss, rich crimson and golden yellow.
And dozens of others. Test carefully the new varieties as they appear, unless you have a chance to see a whole bed of them growing.