Heliotropium
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Read about Heliotropium in the Standard Cyclopedia of Horticulture
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Heliotropium (heliotropic; turning to the sun). Boraginaceae. Heliotrope. Popular glasshouse plants, prized for their flowers and fragrance. Herbs or rarely shrubs, with small fls. in terminal, forking often scorpioid clusters and alternate simple lvs.: corolla short funnelform or salver-shape, the throat mostly open (sometimes constricted); stamens 5, attached to the tube, not exserted, the filaments very short; ovary 4-loculed and splitting into 4 nutlets (or two 2-loculed nutlets) when ripe, surmounted by a simple style.—Species upward of 250, in the warmer regions of the globe, many of them annuals. There is a heliotrope (H. curassavicum, Linn.) native to the U. S., from Del. and S. 111. southward on seashores and in salty soils, with white or bluish fls. and oblong or linear lvs.; another species (H. tenellum, Torr.) in open dry lands from Ky. to Kans. and southward, with white scattered or somewhat umbellate fls. and very narrow revolute lvs.; several species in the southern states and southward; also a naturalized species (H. indicum, Linn.) with bluish scented fls. and oval or ovate-rugose lvs. The garden heliotropes seem to be derived from 2 species. H. peruvianum, Linn., is perhaps the leading species. Fig. 1801. Lvs. oval or oblong-lanceolate, very veiny, not conspicuously narrowed at the base: fls. small, in a close cyme, the corolla-tube little longer than the calyx. Peru. B.M. 141. G. 8:252. Vanilla-scented. H. regale is a garden race of this, with very large clusters and fls. of variable color. Gt. 50, p. 163. H. corymbosum, Ruiz & Pav. (H. grandiflorum, Don), has longer and relatively narrower lvs., which are distinctly narrowed to the base, fl.-clusters larger and more open, fls. nearly twice larger and the corolla-tube nearly twice longer than the calyx; calyx-teeth longer and narrower. Peru. B.M. 1609. Narcissus-scented. Many of the large-trussed and large-fld. garden varieties are apparently of this species rather than of the former; or possibility the two are hybridized. Originally both species were violet-fld. but the colors are now in various shades of purple, and there are white-fld. forms. H. voltaireanum, Hort., is a compact garden form, and said to be a hybrid. P.M. 16: 100. Another species, H. europaeum, Linn., is rarely seen in old collections, and it is sparingly naturalized. It is a hoary-downy annual herb 6-30 in. high, with long-petioled oval lvs., and white fls. in scirpioid racemes. H. incanum, Ruiz & Pav., of W. S. Amer., is perhaps in cult, as a greenhouse shrub: 2-3 ft.: lvs. thick, ovate, crenulate, more or less silky, hoary beneath: fls. white, in forking spikes, the corolla twice exceeding the calyx. Var. glabrum, G.C. II. 22:809, has lvs. rough, nearly destitute of silky covering, broader and more ovate, a denser infl., a larger and more hairy calyx and purple fls. H. anchusaefolium, Poir., of Brazil to Argentina, is said sometimes to be found in gardens and it is recorded as spontaneous in parts of this country; it is odorless: perennial, with 4- angled hispid st.: lvs. lanceolate to linear-lanceolate, sessile, entire: fls. violet, about ¼ in. across. B.M. 8480. L. H. B. Heliotrope, apart from its use as a border plant and for bedding, being a universal favorite, usually forms part of the stock in trade of florists who do a local business, ranking next to the geranium as a pot-plant for spring trade. For cut-flowers in winter it is equally popular, but its lasting qualities when cut are uncertain. Successful growers think that for best results, strong stems and good keeping qualities, it should be grown in a moderately cool, airy house. Some of the best are grown in a house suited to violets and mignonette, where the temperature seldom rises to 50° F. at night. Stout, soft cuttings make the best plants, and root easily in a temperature of 60° F. From the time they are inserted, sufficient water must be given to prevent wilting. A propagating-bed is not required. Ordinary flats will do—the medium half-leaf soil and sand. They must be well shaded for a week or so. They are very liable to the cutting-bench fungus, and should be potted or boxed off as soon as rooted, which should be in ten or twelve days. Any light soil will do, and it need not be rich for the first shift. For winter flowers, cuttings may be taken in July and treated as above. Some of the plants among the spring batch with straight stems may be grown along for standards by taking out the side shoots until 2 feet night. These make handsome drooping specimens. By pruning about midsummer they may be kept in good condition for years. Heliotropes may be grown in the same pots for several years, by using fairly rich top-dressing or weak liquid manure in growing season. Stock intended for spring cuttings is better grown continuously in pots, as the plants lift badly in the autumn. A few left-over bedding-plants may be grown along in pots, purposely for stock. As a matter of fact, stock taken from these pot-plants root more readily than those taken from plants grown outdoors. A good plan is to prune them rather closely a few weeks before the time for taking cuttings comes, say in January. In this way we secure an even lot of cuttings, and all at one time. Heliotrope is extensively used as a bedding-plant, is a favorite in window-gardens, and is much grown by florists for cut-flowers. The ease with which it may be grown either in pots or the garden, the color and fragrance of its dainty flowers, and the continuity of bloom, have all contributed to make it a general favorite. There have been numerous garden varieties and a number of hybrids—white and the different tints of blue predominating. Floral catalogues rarely mention, however, more than six to eight varieties. Madame de Blonay has been a favorite white for years, while Queen of Violets is perhaps the finest of the blues. Chieftain is a lighter tint. Albert Delaux is a variety with golden variegated foliage, but variegated heliotropes are undesirable. Among seedlings double forms occasionally appear. They have no special merit, and are seldom perpetuated. T. D. Hatfield.
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References
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963
External links
- w:Heliotropium. Some of the material on this page may be from Wikipedia, under the Creative Commons license.
- Heliotropium QR Code (Size 50, 100, 200, 500)
