Difference between revisions of "Crocus"

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Crocus (Greek name of saffron). Iridaceae. Low spring-flowering and autumn-flowering garden bulbs; showy, and well known.
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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).
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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.
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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.
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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. (J. N. Gerard.)
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Revision as of 16:08, 11 August 2009


Read about Crocus in the 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. (J. N. Gerard.)


The above text is from the Standard Cyclopedia of Horticulture. It may be out of date, but still contains valuable and interesting information which can be incorporated into the remainder of the article. Click on "Collapse" in the header to hide this text.


Crocus
Crocus longiflorus
Crocus longiflorus
Plant Info
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Liliopsida
Order: Asparagales
Family: Iridaceae
Genus: Crocus
L.

Species
See text.
Wild crocus growing in the foothills of the Eiger in the European Alps.

Crocus (plural: crocus, crocuses or croci) is a genus of perennial flowering plants, native to a large area from coastal and subalpine areas of central and southern Europe (including the islands of the Aegean), North Africa and the Middle East, across Central Asia to western China.

The genus Crocus is placed botanically in the iris family (Iridaceae). The plants grow from corms and are mainly hardy perennials, and are found a wide range of habitats, including woodland, scrub and meadows.

There are about eighty species of crocus, of which approximately 30 are commonly cultivated. Their flowers are cup-shaped, solitary, salverform, tapering off into a narrow tube; they vary enormously in colour, though lilac, mauve, yellow and white are predominant. The grass-like, ensiform leaf generally shows a white central stripe along the leaf axis. The leaf margin is entire. All crocuses typically have three stamens.

The name of the genus is derived from the Latin adjective crocatus, meaning saffron yellow. The spice saffron is obtained from the stigmas of Crocus sativus, an autumn/fall-blooming species.

True autumn crocuses

Most true autumn crocus flower in September to November in the northern hemisphere. Some flower before their leaves appear. Autumn/fall flowering species include: Crocus banaticus (syn. C. iridiflorus), C.cancellatus, C. goulimyi, C. hadriaticus, C. kotschyanus (syn. C. zonatus), C. laevigatus, C. medius, C. niveus, C. nudiflorus, C. ochroleucus, C. pulchellus, C. sativus (saffron crocus), C. serotinus, C. speciosus, C. tournefortii. Crocus laevigatus has a long flowering-period which starts in late autumn or early winter and may continue into February.

In cultivation

As one of the first flowers to bloom in spring, the large selected hybrid Dutch crocus are popular with gardeners. However, in areas where snow and frost occasionally occur in the early spring it is not uncommon for early-flowering crocuses to suddenly wither and die from a unseasonable frost or snowfall.

Most crocus species and hybrids should be planted in a sunny position, in gritty, well-drained soil, although a few prefer shadier sites in moist soil. Some are suitable for naturalising in grass. The corms should be planted about 3–4 cm deep; in heavy soils a quantity of sharp grit should be dug in to improve drainage.

Some crocuses, especially C. tommasinianus and its selected forms and hybrids (such as 'Whitewell Purple' and 'Ruby Giant') seed prolifically and are ideal for naturalising. They can, however, become weeds in rock gardens, where they will often appear in the middle of choice, mat-forming alpine plants and can be difficult to remove.

History

The first crocus seen in the Netherlands, where Crocus species are not native, were corms brought back from the Holy Roman Emperor's ambassador to the Sublime Porte, A. Ghislain de Busbeq, in the 1560s. A few corms were forwarded to Carolus Clusius at the botanical garden in Leiden. By 1620, the approximate date of Ambrosius Bosschaert's painting (illustration, left), new garden varieties had been developed, such as the cream-colored crocus feathered with bronze at the base of the bouquet, similar to varieties still in the market. Bosschaert, working from a preparatory drawing to paint his composed piece, which spans the whole of Spring, exaggerated the crocus so that it passes for a tulip, but its narrow, grasslike leaves give it away.

Species

Cloth of gold (Crocus angustifolius)
from Curtis's Botanical Magazine 1803

The taxonomic characteristics are based mainly on the presence or absence of a prophyll (a basal spathe) and the aspect of the style and the corm tunic.

1 Subgenus Crocus

A. Section Crocus
Series Kotschyani
Series Longiflori
Crocus serotinus subsp. clusii
Series Scardici
Series Verni
Crocus vernus subsp. vernus
Crocus vernus subsp. albiflorus
Series Versicolores
Series Crocus
B. Section Nudiscapus
Series Aleppici
Series Biflori
Series Carpetani
Series Flavi
Series Intertexti
Series Laevigatae
Series Orientales
Series Reticulati
Series Speciosi

2. Subgenus Crociris

Misuses of the name crocus

Though some true crocus bloom with the fall (autumn) rains, after summer's heat and drought, the name "autumn crocus" is often misused as a common name for Colchicum, which is in the lily family (Liliaceae), and which has six stamens; it is also (confusingly and incorrectly) known as "meadow saffron". The so-called "prairie crocus" (formerly Anemone patens, now Pulsatilla patens or P. ludoviciana) belongs to the buttercup family (Ranunculaceae).

References

  • Brian Mathew, Christopher Grey-Wilson, Bulbs, (ill. Marjorie Blamey), Collins, 1981
  • Brian Mathew, Crocus: A Revision of the Genus Crocus, Timber Press, 1983. ISBN 0-917304-23-3
  • Brian Mathew, Flowering Bulbs for the garden, Collingridge/Royal Botanic Gardens, Kew, 1987. ISBN 0-600-35175-0

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