This old favorite has possibly been grown as long as there has been any greenhouse to protect it in winter. All we grow are varieties of H. Peruvianum. It always was a favorite for our summer flower garden, either in beds or in the mixed border. As a cut flower it has its delicious fragrance to commend it, but it wilts rather quickly when cut.
You can neither lift old plants with success nor root the cuttings that you take from the plants grown outside, so you should always grow a few plants over summer in pots, and move them to the greenhouse before frost, when if the shoots are shortened back you will get young, tender cuttings that root quickly where there is some bottom heat. No cuttings root more quickly or surely than heliotrope in January, February and March, and your stock can be then increased to any extent. Young plants soon spoil if stunted in small pots, and to keep them thrifty they must be shifted on and occasionally pinched. For this reason you don't want a large stock too early in the winter. This is a plant that does finely in a mild hotbed after the middle of April. Thousands are sold in our markets every spring.
You often see a plant of heliotrope planted out at the end of a greenhouse covering a large space. Such a one I have. It gets cut back to the main shoots every September, and during winter yields bushels of flowers, which are occasionally asked for. It also provides me with an abundance of cuttings at any time during winter that I may need them.
Heliotropes are often grown as standards and are used as conservatory plants or plunged out in the flower garden. They certainly make a fine appearance. Have a bed of heliotrope of the ordinary size of plants, into which plunge a dozen of the 3-foot standards- or any other dwarf flowering plant could be the groundwork. They are easily grown.
Choose a strong, healthy, young plant, and without any pinching encourage it to run up three feet, and then stop it, keeping all lateral growths pinched off except a few near the top. You can let these plants rest in a cool house with little water during winter and start growing again in March. The head can be left to grow naturally as you would a standard rose, but they look much better tied to a wire frame as we do standard chrysanthemums. I can't say that the standard heliotrope is a good investment for the florist, but when time and space allow it is a great ornament to our flower gardens.
Heliotrope is popularly supposed to be easily injured by tobacco smoke. If a strong dose is first given it does injure it, but after a few fumigations it does not notice it more than a geranium. Why should it not get inured to it? I have noticed frequently that it does, although it does not need any smoke.
A rust is its worst enemy, which will not attack it unless it gets root-bound and stunted. The heliotrope grows finely in a temperature of 50 degrees, but will not endure the slightest frost. There are constantly new varieties being sent out. A few good ones are:
Le Cid; semi-dwarf, robust, large panicles, mauve, with clear white eye.
Le Poitevine; great size, mauve, violet and azure; very free and continuous in bloom.
The Giant; enormous panicle of bloom, color a rosy violet, white eye.
Cameleon; bright blue, large panicles and florets.
Albert Delaux; pretty variegated foliage, purple flowers.
White Lady; the best of the white or light varieties.