This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
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. sativus 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. (J. N. Gerard.)
A. Blooming in spring (sometimes in midwinter and continuing toward spring).
B. Style-branches entire or merely toothed.
C. Flowers yellow, at least inside (varying to whitish forms): basal spathe absent.
D. Outer segments striped or feathered outside.
Cloth-of-Gold Crocus. Fig. 1114. Corm 3/4in. diam.: leaves 6-8 in a tuft, reaching to the flower, narrow-linear, with revolute edges and a central band of white: upper spathe 2-lvd.: perianth-segments 1 1/2 in. or less long, orange-yellow, becoming reflexed, the outer ones brownish or striped on the outside; anthers orange, longer than the filaments; style-branches long and spreading. Crimea. B.M.652 (adapted in Fig. 1114). - Blooms very early, Feb., Mar.
Fig. 1114. Crocus susianus. (X 1/2) cc. Flowers lilac, purple or white.
2. chrysanthus, Herb, (not B.R. 33:4, fig. 1, which=C. Olivieri variety Suterianus). Corm small: leaves as high as the flower, very narrow: upper spathe 2-lvd., nearly as long as perianth-tube: perianth-tube 2-3 times as long as the segments, the latter 1 1/4 in. or less long, and plain orange-yellow (varying tinted or striped on the outside, or even nearly white); throat glabrous; anthers orange, twice as long as the roughened filaments; style-branches red-orange. Macedonia and Asia Minor. Gn. 74, p. 140. variety albidus, Hort. Flowers whitish. Gn.W. 25:229.
Supposed to be a hybrid between C.moesiacus and C. susianus, and known only in cultivation: blooms with C. moesiacus: leaves only 4-6, narrow-linear, reflexed edges, white-banded: upper spathe 2-lvd.: perianth-tube short, the segments 1-1 1/2 in. long, bright orange, the outer ones striped and feathered with brown on the back; anthers pale orange, a little longer than the filaments; style-branches somewhat overtopping the anthers. Mar.
dd. Outer segments not striped (at least not in the specific types).
Dutch Crocus. Later: corm larger: leaves 6-8 in a tuft, overtopping the flower, narrow-linear, with reflexed edges and white central band: upper spathe 2-lvd., inner valve very narrow or obsolete; segments very obtuse, bright yellow, 1 1/2 in. long, one-half to a third the length of the tube: anthers pale yellow, hastate at the base, somewhat longer than the filaments; style-branches overtopped by the anthers. Transylvania to Asia Minor. B.M. 2986. - Variable. A sulfur-yellow form is C. sulphureus, Ker. B.M. 1384. There is a striped form. B.M. 938. A cream-white form is C. lacteus, Sabine.
Corm 3/4in. diam.: leaves 3-4, as tall as the flower, very narrow: upper spathe 2-lvd.: perianth-tube exserted; segments bright orange-yellow, 1 in. or less long, not striped nor colored outside; anthers orange-yellow, much longer than the filaments; style-branches red-orange. Asia Minor. - Blooms early.
Corm globose, 1 in. diam. with matted fibers: leaves 8-12, very narrow, with reflexed edges and a central white band: upper spathe of 1 or 2 membranous valves: perianth-tube shortly exserted; segments about 1 in. long, bright orange-yellow and not striped, the outer ones grayish brown on the outside; anthers orange-yellow; style-branches entire and orange-yellow. Turkestan, etc. variety dytiscus, Bowles, has the outer segments deep brown outside and with narrower margins of yellow.
D. Basal spathe (rising directly from the corm inside the leaves) absent.
Scotch Crocus. Corm 3/4in. or less in diam.: leaves 4-6, overtopping the flowers, very narrow, with deflexed edges and a white central band: upper spathe 2-lvd.: perianth-tube exserted, the segments 1 1/2 in. long, purple-tinged, the outer ones 3-striped down the back, the throat bearded and yellowish; anthers orange, exceeding the filaments; style-branches orange-red. S. and S. W. Eu. B.M. 845. - Runs into many forms, some of them almost white. Some of the named botanical forms are: variety argenteus, Baker (C. argen-teus, Sabine. C. praecox, Haw. C. lineatus, Jan). Less robust and with only 3 or 4 leaves to a tuft and smaller flowers more tinged with purple and the outer segments dark-striped outside. Italy. B.M. 2991 (as C. minimus. variety pusillus, Baker (C. pusillus, Tenore). Flowers smaller than m variety argenteus, paler, the 3 outer segments striped with dark purple. Italy. B.R. 1987 (variety estriatus, with petals pale purple and not striped). variety Weldenii, Baker (C. Weldenii, Hoppe), with uniform slaty purple limb. Dalmatia. B.M. 6211. variety Adamii, Baker (C. Adamii, Gay). Limb pale purple, the outer segments 1-colored or with 3 pale purple stripes.
Caucasus. B.M. 3868 (as C. annulatus variety Adamicus). variety nubigenus, Herb. segments very small and nearly white, the outer ones with a broad band of purple on the back. Asia Minor. variety Pestalozzae (C. Pestalozzae, Boiss.). Small-flowered, with 1-colored whitish segments Asia Minor. variety Alexandri, Hort. (C. Alexandri, Velen. Flowers larger than in C. biflorus type; outer segments flushed all over the back with bright lilac and with a narrow margin of white, or often with only feather-like stripes on white grounds. B.M. 7740.
(C. Sibthorpianus variety stauricus, Herb.). Corm globose, 3/4in. or less diam., the tunic bristle-ringed at top: leaves 3-6 in the tuft, as high as the flower, very narrow, with reflexed margins and a white band: upper spathe 2-lvd.: perianth-tube little exserted; segments 1 in. or less long, unstriped, pale or dark lilac, the throat yellow and glabrous; anthers orange, twice the length of the slightly papillose filaments. Armenia, Kurdistan. B.M. 6852B. Gn. 74, p. 212. Early.
dd. Basal spathe present.
E. Throat of perianth glabrous.