Oncidium orchids are a genus of about 350 species of epiphytes, very common in almost all of tropical America. The genus is characterized by the presence of two or three large leaves that are formed by the pseudobulbs, whose axils sprout the flowering stems.
Generally the flowers have wings at the base of the ginandrio and a toothed crest at the base of the labellum.
Given the variety of different species, these orchids can have variable characteristics, with large and small specimens. The O. Tigrinum variety is native to Mexico, where it grows on oaks and grow at temperatures around 12/15 ° C.
The oncidium orchids develop, in nature, in places that have not too high summer temperatures, therefore, to obtain a good development of these plants it is advisable to keep them in a very humid and well-shaded place all year round; In winter the ideal temperature for oncidium tigrinum is around 12/15 ° C.
The optimal breeding ground for these orchids consists of a mixture of two parts of osmunda fiber and a finely chopped part of sphagnum peat, with the addition of river sand. It should be carefully checked that the chosen substrate does not allow water stagnation, as this type of orchid does not tolerate it and can quickly spoil. It is essential, however, to maintain the right degree of humidity, proceeding to vaporize the leaves with water at room temperature when the temperatures are higher.
It is important, then, to place these plants in environments that present good air circulation, without however subjecting them to cold air currents, which are harmful for their growth.
The oncidium tigrinum orchids are divided when the new shoots appear, and they are repotted every 2-3 years, to eliminate the old substratum which over time is deteriorating and no longer provides the necessary support for the roots of these epiphytic plants. It is essential, when proceeding with repotting, to pay close attention to the roots which are rather delicate and fragile; to avoid breaking them, it is good to wet them before proceeding with the repotting and division to obtain new plants.
The multiplication and repotting operations should be carried out between the end of summer and the beginning of autumn. These plants, being epiphytes, can also live without being placed in a vase, but resting them on trunks or barks, but it is essential to vaporize the roots regularly.
It is advisable to guard against the red spider, which causes the formation of bleached spots on the leaves. To eliminate the problem it may be sufficient to proceed with more water vaporization on the leaves, as these pests do not like excess moisture. There are also special insecticide products that can quickly eliminate the problem.
Other problems may arise due to unfavorable environmental conditions, such as incorrect temperature or exposure to direct sunlight during the hottest days.
O.Varicosum is a particular variety of this type of orchid that is widespread in Brazil; it has flattened pseudobulbs, with 2 lance-shaped leaves, flowers gathered in panicles, yellow-green, with brown stripes, the labellum is golden yellow, with a dark spot on the crest.These plants, in order to grow at their best, need dry and temperate climates during the winter season and a warm and humid environment during spring and summer.Oncidium Orchids - Oncidium tigrinum: O.Altissimus
This variety comes from the West Indies, has flattened pseudobulbs, with a single leaf, and yellow flowers with brown spots. They are a rather resistant variety, which adapts to living in climatic conditions that can show remarkable changes in temperature.