Dendrobium are a genus of orchids that has more than a thousand species, not counting the dozens of greenhouse hybrids, very common in the market. In nature these orchids live in Asia and Australia, and in most of the Indian Ocean islands, crossing so many climates: from the cold of the Asian highlands, to the dry heat of the Australian deserts.
They produce small oval, pointed, light green leaves; plants over time develop numerous pseudobulbs, in which they store nourishment during the winter, to use it the following year. The flowers and plants can have various sizes, given the number of species present. Often the larger species produce long arched floral spikes, while the small ones produce erect floral stems.
They bloom in spring, more rarely in autumn, and the flowers can be of various colors, with pink and yellow among the predominant colors.
They are predominantly epiphytic plants, although there are some lithophytes and few terricolous species; in order to better describe these plants they are often divided into numerous groups, which bring together the most similar species in terms of cultivation climate.
In reality in the nursery we generally find hybrids somehow related to Dendrobium nobile, a deciduous species; in addition to these we sometimes find evergreen dendrobium, of which it is easier to find only cut flowers, to prepare bouquets or bouquets.
We can therefore generalize and describe only two large groups of dendrobium, and almost certainly the plant you received as a gift falls into one of these two types.
Relatives of the Dendrobium nobile, these orchids are epiphytes and produce pseudobulbs of almost cylindrical shape, slightly enlarged. Pseudobulbs produce large stems, vaguely reminiscent of canes, some of which bear leaves, while others produce flowers of various colors. The flowers bloom in spring, when the plant needs a good brightness and fairly regular watering, avoiding to leave the soil dry for a long time. From April to September let's water regularly, and every 15-20 days let's mix some specific fertilizer for orchids with the irrigating water.In the summer we can place the dendrobium outdoors, in a luminous place, but not directly exposed to solar rays; It is important that they receive good ventilation and good environmental humidity.In autumn we thin the waterings, so that the plant goes into vegetative rest; if possible we take our dendrobium in a greenhouse, where it can receive temperatures close to 10 ° C. If you cultivate in the apartment at almost constant temperature these plants tend to stop flowering, it is therefore important that they enjoy a few weeks of dry and cool climate.Let's avoid watering the plants, the climate is cooler and less need watering. At this time of year they will lose much of the foliage; however, if we note that the stems tend to shrink and dry too much, we supply small amounts of water, so as to moisten the substrate.Watering will resume when the plant emits the first shoots, at the apex of the pseudobulbs.There are deciduous dendrobium that need watering throughout the year, with a slightly warmer climateThese are tropical dendrobiums; they are often small sized species, with very bright colored flowers.These dendrobium do not need a dry period, and should be watered throughout the year, avoiding leaving the substratum completely dry for short periods of time.Some species prefer warm temperatures throughout the year, others like the cool in winter, when the temperature should not exceed 12-15 ° C; position them in a well-lit place, avoiding blows of air.The climate must be perennially well humid; for this reason it is good to place the dendrobium in a pot holder full of clay, which must always be kept moist.THE DENDROBIUM IN BRIEFFamily, genus, species Orchidaceae, gen. dendrobium, more than 1600 speciesArea of origin Southeast Asia, OceaniaType of plant Epiphytic orchidSize at maturity From 10 cm up to 6 metersCulture From medium to difficultExposure Very brightSubstrate Bark, clay or other inert material; raftirrigations Frequent, with periods of suspension depending on the groupSoil humidity From fresh to dry, depending on the periodsoil pH Slightly acidicGrowth averageRusticitа delicateMinimum temperature The most resistant at most 5 ° C, the most delicate 12 ° CIdeal temperature 15-20 ° CPropagation Division, keiki withdrawaluse Vase, raft. In the apartment or in the greenhouse. Outdoors in spring-summerRepotting
Periodically the dendrobiums tend to fill the container with new pseudobulbs; in autumn we can repot our plant, using a good specific substrate for orchids.
If desired, it is also possible to propagate the plants, dividing the tufts of pseudobulbs; or we can also simply remove the older pseudobulbs and keep only the young and swollen ones.
Dendrobiums sometimes tend to produce new plants attached directly to the nodes of the stems, called kieki; these young plants have their own roots, so they can be detached from the mother plant and repotted individually.
Species and varieties
Giving a unitary description of the dendrobium is very difficult. The genus is in fact composed of at least 1600 widespread species, in the spontaneous state, in a very wide area and with great climatic differences, from South-East Asia and Oceania, to the Himalayan slopes, to the islands of Polynesia and New Guinea.
Their appearance also varies greatly: they can be erect or decombent, large (some exceeding 6 meters in length) or small. The flowers are solitary or in groups, from very large to very small and they are truly multi-faceted.
Beyond aesthetics, what matters most to enthusiasts, however, are the cultural needs. Some dendrobiums better tolerate low temperatures; Others need greenhouses and special equipment to keep the climate and lighting mostly stable in every season.
For this purpose we can divide the genre into six groups.
The more we respect the natural vegetative cycle of these orchids and the more blooms we get. It is indeed essential to facilitate a winter rest period, with consequent consumption of the reserves contained in the pseudobulbs to induce, at the first temperature increase, the production of the buds. In this perspective the right modulation of irrigation is a very important aspect, given that in nature they are subjected to a long and hard dry season.It is essential to always keep the ambient humidity high (with vaporisations or with specific appliances) and to make sure that the pseudobulbs do not wither too much. Let us also remember to use rainwater or demineralised water. Here are some tips for each specific group:- Those of the first group need abundant irrigation in spring-summer that must be completely interrupted when autumn arrives. We resume as soon as we see the first buds born and continue until the end of flowering. At that point we will interrupt again until the view of the vegetative jets.- The dendrobium of the second group need abundant irrigation during the summer, but we must be very careful at the time of flowering and vegetative development.- The third and fifth groups require abundant irrigation and fresh substrate at all times of the year.- The fourth group also wants wet substrate for most of the year, except for a short period coinciding with the interruption of growth.- For the sixth group it is important to administer water during flowering and to limit, for the rest of the year, to abundant leaf vaporisations, thus avoiding the onset of rottenness at the level of the pseudobulbs.We fertilize the evergreens twice a month and once the deciduous ones, leaving out however during the rest period. Even very frequent but very dilute foliar fertilizations are appreciated by these orchids.GroupMost widespread speciesirrigationsVegetative period needs and temperatureNeeds and Temperatures in autumn and winter1°noble, chrystathum ewardianumFrom March to OctoberIn winter suspendT. min. 13 ° CThey can be kept in a tempered greenhouse, in an apartment or outsideT. just below 10 ° C are useful for stimulating flowering. Cold greenhouse2°anosmum, findlayanum, heterocarpum, pierardiiOnly during the vegetative period,moderate in bloom. In winter suspendThey want constant temperatures all year, with minimums of at least 13 ° C. The ideal is to grow them in a tempered greenhouse.3°densiflorum, farmeri, fimbriatum, thyrsiflorumRegular throughout the yearT. min. 13 ° CThey can be kept in a tempered greenhouse, in an apartment or outsideT. just below 10 ° C are useful for stimulating flowering. Cold greenhouse4°formosum, infundibulum, sanderae, schutzei, macrophyllumRegular throughout the yearWarm greenhouse, apartment or outside: minimum temperature 15 ° C during the night, maximum 20 ° C during the day.Warm greenhouse with about 12 ° C at night and 15 ° C during the day5°Warm greenhouse with about 12 ° C at night and 15 ° C during the dayRegular throughout the yearFrom temperate to hot greenhouse. About 20 ° C during the vegetative periodWarm greenhouse at minimum 15 ° C6°biggibum and phalaenopsisOnly during the vegetative period. In winter suspendFrom temperate to hot greenhouse. About 20 ° C during the vegetative periodLight not direct, but very intenseHot greenhouse, temperatures never below 16 ° CDendrobium - Dendrobium: Other crop indications
Being epiphytic plants the ideal is to supply them with a substrate similar to the natural one, that is bark or inert material. You can then use bark, specially treated, expanded clay or alternate between large and small pieces of polystyrene. We always choose rather small vessels so that we can frequently irrigate, avoiding excessive water deposits that can cause rot.
An excellent method of cultivation is also that on a raft: you can set the plants by making them stick to branches or degrees of cork bark, which they will then cling to. From hanging they will also be very decorative.
Repotting takes place every two years, always during the vegetative period, when the new buds and rootlets are shown.