|Standard Cyclopedia of Horticulture|
Crocus (Greek name of saffron). Iridaceae. Low spring-flowering and autumn-flowering garden bulbs; showy, and well known.
Stemless plants (the grass-like Lvs. rising from the ground or corm), with solid bulbs or corms: fls. showy, in many colors, funnel-shaped and erect, with a very long tube and 6 nearly or quite equal segms.; stamens 3, attached in the throat of the perianth and shorter than the segms.; style 3-cleft, the branches entire or forked or much fimbriated; ovary 3-loculed: seeds many, nearly globular: fr. an oblong 3-valved caps.— Probably 75 species, many of them variable, in the Medit. region and extending into S. W. Asia. The fls. open in sunshine. They come in fall or spring, but the best-known species are spring-flowering, which are amongst the earliest and brightest of spring bloom. Crocuses force easily (see Bulb). A half-dozen corms may be planted in a 4-in. pot for this purpose. Crocuses are scarcely known in the American trade under their species names. Inasmuch as the flowers of the common crocus close when taken out of the sun, they are not popular as window-garden or house subjects. Crocuses have been much hybridized and varied. There are many color-forms. The common crocuses of the trade have descended from C. vernus chiefly, but C. susianus, C. moesiacus, C. stellaris, C. biflorus and C. sativus are frequent. The Dutch bulb- growers cult, many species, and these are offered for sale in their American lists; the species are therefore included in the following synopsis. In this account, the treatment by Baker is followed (Handbook of the Irideae).
Botanically, the genus divides itself into three groups on the characters of the style-branches: the branches entire, once-forked or fimbriated at the apex, or cut into several capillary divisions. Horticulturally, the species fall into two groups,—the spring-flowering and the autumn-flowering. These groups are not so definitely separated as it would seem, however. Some of the species bloom in winter in regions in which the ground does not freeze hard; others begin to bloom in July or August; some may continue to bloom till winter closes in. Yet these two flowering periods mark very important differences in the utilization of the plants and the primary division in the following treatment is made on this basis. The colors are now much varied by cultivation and hybridizing, but they are well marked in the specific types as a rule. They run largely in yellow, white and purple.
The covering or tunic of the bulbs may be uniformly membranaceous, or it may be composed of strongly reticulated or parallel fibers. Fig. 1113. The flowers appear usually just in advance of the grass-like foliage- leaves. The floral leaves are small and more or less dry or scarious and arise directly from the corm and may be seen as a spathe-like structure inside the leaf-tuft; this is usually known as the basal spathe. The real spathe subtends the bloom, and it is always one-flowered; this floral spathe may be one-leaved or two-leaved.
Culture.—Many forms of crocus are well known, where they are justly valued as among the showiest and brightest of winter and spring flowers. They thrive in any ordinary soil. About two-thirds of the species are classed as vernal and the remainder as autumnal flowering; but the various members of the tribe would furnish nearly continuous bloom from August to May were the season open. While there are numerous species interesting to a botanist or a collector, practically the best for general cultivation are Crocus Imperati, C.susianus (Cloth of Gold crocus) and the Dutch hybrids, mostly of C.moesiacus. These bloom in about the order named. The rosy flowers of C. Imperati may be expected with the earliest snowdrops. The named species, having shorter flower-tubes than the Dutch hybrids, are not so liable to injury by the severe weather of the early year. The autumnal species are not satisfactory garden plants, the flowers mostly appearing before the leaves, and being easily injured. C. speciosus and C. satvus are probably the most satisfactory. The latter species has been cultivated from time immemorial, the stamens having a medicinal reputation, and being a source of color (saffron). The cultivation of this species is a small industry in France, Spain and Italy.—The corms of crocuses should be planted about 3 or 4 inches deep, in a well-worked and perfectly drained soil which is free from clay or the decaying humus of manure. They should be set only 2 or 3 inches apart if mass effects are desired. They may be planted in September or October for bloom in the spring or the following autumn; or the autumn kinds may be planted early in spring. The corms should be carefully examined and all bruised and imperfect ones rejected, as they are very susceptible to attacks of fungi, which, gaining a footing on decrepit corms, will spread to others.—The careful gardener will examine all exotic small bulbs annually, or at least biennally, until they show by the perfection of their new bulbs that they have become naturalized, or are suited to their new environment. In this case they may be allowed to remain until crowding requires their division. This examination should take place after the leaves are matured and dried up. Inasmuch as new corms form on top of the old ones, the plants tend to get out of the ground; it is well therefore to replant the strongest ones every two or three years. Increase may be had from new corms which are produced more or less freely in different species on top or on the sides of old corms. —Seeds are often produced freely, but are likely to be overlooked, as they are formed at the surface of the soil. These germinate readily and most freely at the growing time of the plant. They should preferably be germinated in seed-pans, which should be exposed to freezing before the natural germinating time. Seedlings usually flower the third season.—The dutch hybrid crocus is often useful for naturalizing in the lawn, although the grass may run out the plants in a few years, if the bulbs are not replaced by strong ones; they will not last more than a year or two if the foliage is mown off, but if the foliage is allowed to remain until ripe and if the lawn is fertile, the plants may remain in fair condition three or four years or more. CH
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Pests and diseases
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1 Subgenus Crocuswp
- A. Section Crocuswp
- Series Longifloriwp
- Series Verni wp
- B. Section Nudiscapuswp
- Series Reticulatiwp
2. Subgenus Crociris wp
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963