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Wednesday, December 05, 2007

Dendrobium

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Decription Dendrobium hybrids are the largest group of orchid sub-tribe which contain more than 1.500 species and possibly thousands of hybrids. They are found from the orient and tropical Asia down to Australia.
Dendrobium plants vary in size, some being smaller than a matchbox, others large, robust specimens measuring over 1 meter. They are epiphytic by nature and require good light and ventilation. Some dendrobiums are deciduous while others are evergreen. Some have pseudobulbs and others have jointed stems resembling canes. Because of the complexity of this genus, some varieties may prove to be shy to flower.The flower spikes can be over two feet tall with over twenty blooms on them. The flowers last for 6 to 8 weeks and they make excellent cut flowers. The blooms are all the colors of the rainbow - pinks, lavenders, reds, yellows, oranges and many mixed color combinations. Lavender or white flowers are borne in profusion on a well-grown plant and are long lasting. They are a prolific group in which offset plantlets are frequently produced on the cane. When each offset has produced several aerial roots, it can be cut from the parent plant and will frequently flower after one year of growth. Although the color range is varied most hybrids offered for sale are usually lavender, white, golden-yellow, or combinations of these colors. Some of the more unusual species and hybrids can be bluish, ivory colored, brilliant orange or scarlet, or have exotic markings. Most of the evergreen Dendrobiums are not fragrant however the deciduous species can have fresh citrus scent or smell of raspberries. Care and cultivationDendrobium needs bright, cool light; allow to dry slightly between waterings when not in bloom.Dendrobium prefer open compost of either tree-fern fibre and perlite or bark-based peat. Whichever medium is used, it must be open enough to maintain some air around the roots. They cannot tolerate wet, soggy composts, which will inevitably damage and rot their wiry roots. Occasional misting on the foliage will help any moisture loss occurring during very warm days in tropical and sub-tropical climates. They can stand temperatures from 45° to 95° F (7°-35° C), the ideal temperatures are 60°-85° (16°-30° C).Repot once every two years in Spring, after blooming, or when new growth starts. A mix of 10 parts fine-grade Fir-bark and 1 part orchid mix will work well in 6" pots and smaller, while medium-grade Fir-bark works well in larger pots.High-nitrogen fertilizers (25-9-9) can be used year-round at one teaspoon per gallon of water.PropagationDendrobium can be propagated by cutting the old canes between the sections and laying them on fresh, damp compost. Plantlets will quickly develop at the nodes. Dendrobiums are one of the few types of orchids that will bloom from the old pseudobulbs/canes, and they also bloom from the new growth.

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