Friday, December 5, 2014

Tulipa spp.

Common Names: tulip
Family: Liliaceae (lily Family)

There are some 120 species of wild tulips and more than 2300 extant named varieties of garden tulips. All tulips are hardy bulbous perennial herbs with mostly basal, straplike leaves. The flowers are usually cup or bowl shaped and usually have six tepals. However, there are tulips with star shaped flowers, double flowers, and tulips with tepals that are reflexed, elongated, or fringed. Most tulips produce a single flower on a central stem, but some species bear multiple flowers. Most tulips bloom in the spring. Tulips have been developed in nearly every color except true blue. Irregular stripes, streaks or speckles in tulip blossoms are called "broken" colors and are the result of a virus infection. Tulips with broken colors are often very attractive, and were formerly very valuable, but nowadays are hard to find.
By international agreement, tulips are classified into 15 divisions and tulip names are registered in the "Classified List and International Register of Tulip Names", published in the Netherlands by the Royal General Association of Bulbgrowers. The 1996 edition lists some 3000 names for tulip species, garden cultivars, extinct cultivars and invalid names that are synonyms. The first 11 divisions include the garden tulips, all presumably derived from a single ancestor; the other four divisions are "botanical" tulips which are wild tulip species and hybrids of them.

The wild species of tulips are all native to temperate regions of the Old World, mainly central Asia. They come from climates that have cold winters and dry summers and grow from near sea level to high in the mountains, usually on arid, stoney, hillside meadows. Based on genetic evidence, it is believed that all of the myriad varieties of garden tulips originated from a single wild ancestor. However, no one knows for sure what that ancestor was, and it is possible that whatever species did give rise to garden tulips is no longer extant.

Growing tulips is a little more difficult than most spring flowering bulbs. Tulips should be planted in beds without competition from other plants. Fertilize with phosphorus and potassium, but keep the nitrogen down, as this leads to excess vegetative growth and fungus disease. Bonemeal or superphosphate is recommended. If the soil is acidic, it should be neutralized with limestone. Tulips should not be planted in the same place for more than 2 or 3 years in a row.
Light: Tulips appreciate full sun, and do best when planted on a south facing slope. However, in zones 7-10 they should be positioned in a site that is partly shady, or at least shady during the midday.
Moisture: Tulips need a soil that is well drained but still capable of holding some moisture during dry periods in the spring growing season. If it is necessary to water, do so between the plants, avoiding the stems. Tulip bulbs need to be kept dry during the summer and winter.
Propagation: Tulip bulbs should be set out at the end of autumn for flowering the following spring. If set out too soon, they may begin to grow and get caught by frost; too late and they won't have enough time to develop an adequate root supply. The bulbs of garden tulips are planted so that their tops are 6-8 in (15-20 cm) beneath the ground surface - up to 12 in (30.5 cm) deep if you plan to leave the bulbs in the ground for more than one season. (Note that this is deeper than for most bulbs.) The bulbs of botanical tulips are planted just 4-6 in (10-15 cm) below the ground surface. Tulips can be maintained perennially if the bulbs are lifted after flowering and allowed a dry, airy rest during the summer. Dig the bulbs after the leaves begin to yellow, but before they have turned completely brown. There are some cultivars (in the Kaufmanniana, Greigii and Fosteriana divisions especially) and many species (T. sprengeri, T. sylvestris, for example) that can be naturalized in a meadow or lawn and allowed to remain in the ground. Mature tulip bulbs produce offsets that can be separated after lifting and planted out at the appropriate time. It may take several growing seasons before the young offset bulbs start flowering themselves. It is possible to stimulate increased production of offset bulbs by making a cut on the mother bulb with a knife.

Tulip breeding takes skill and patience. Most of the modern hybrids are sterile, and seed can be produced only by hand pollinating between two different cultivars. Of course, you never know what will result from such crosses, and it takes 5-10 years of growth before a tulip produces its first flower. Most of the wild tulip species produce seed abundantly. However, germination requires exacting conditions, usually including a period of cold storage.

Tulips are usually grown in formal beds or in containers, and are at their best when grown in masses. Many gardeners, especially when design is critical, plant new tulip bulbs each year and avoid the trouble of lifting and storing the bulbs, or the disappointment of sporadic bulb survival. Tulips are ideally suited for forcing in containers: In autumn or early winter plant 5 or 6 bulbs in a 6 in (15 cm) pot and cover with fine mulch or potting soil. Keep the pot in a cool greenhouse or cold frame until it is filled with roots, usually after 6-10 weeks. Then, put the pot in a warm room until growth is well underway. Once flowering begins, the pot can be displayed in the house. Don't overlook the use of wild or botanical tulips in the rock garden or in a naturalistic meadow garden. The species tulips and their hybrids usually can be left in the ground permanently.
Tulip flowers lack nectaries and therefore are not attractive to butterflies and most other insects.

Ogier Ghislen de Busbecq, Ambassador from the Holy Roman Empire to the Ottoman Empire, was apparently the first educated European to see the beautiful tulips growing in the gardens of Constantinople (now Istanbul). Apparently the Turks had been growing, hybridizing, selecting and appreciating tulips for centuries, although the flowers were unknown in Europe. Busbecq sent tulip bulbs back to the Imperial Gardens of Vienna in 1554. A few years later the French botanist and gardener, Carolus Clusius ("The father of all beautiful gardens"), was appointed Prefect of the Imperial Gardens, and spent the next 14 years selecting and hybridizing Busbecq's tulips. In 1593 Clusius accepted a professorship at Leiden University in Holland. He brought his tulip collection with him, and established the Hortus Academicus, the first botanical garden for ornamental rather than medicinal plants. By this time Dutch gardeners already had tulips, but they weren't nearly as special as those of Professor Clusius. Unfortunately the good doctor was more interested in his hybridizing experiments than in selling his precious bulbs. So, on what was probably a dark and stormy night, lawless bulb rustlers broke into the botanical gardens and stole Clusius' tulips. The stolen bulbs started the Dutch tulip industry and spawned the "tulipmania" of the early 1600's, in which gardeners, merchants, investors and speculators paid exorbitant sums for special (often broken colored) tulip bulbs. Some people spent the equivalent of thousands of dollars for a single tulip bulb. The madness lasted for several years and spread throughout Europe, but ended abruptly in 1637 when the supply caught up with demand.

Today tulips are still the world's most important ornamental flower cash crop. The Dutch produce more than 3 billion tulip bulbs annually; some are grown out for cut flowers but most are exported (especially to North America, Germany and Japan) as bulbs. Tulips are grown commercially in the United States, too - especially in the Skagit Valley of northwestern Washington, and around Holland, Michigan; both areas hold annual tulip festivals.

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