A species that is the basis of numerous horticultural hybrids and varieties, Dendrobium bigibbum represents, along with Dendrobium nobile, the most popular taxon in the horticultural trade, both as potted plants and as cut flowers. It originates from the tropical area of Australia (North Queensland) and New Guinea.
The species grows on trees and rocks in tropical jungle areas, in coastal thickets, near rivers and swamps, as well as in open tropical forests of Queensland, Australia, southern New Guinea, and on a single island in Indonesia.
From a taxonomic point of view, the species was initially described by the renowned botanist John Lindley, being published in the periodical Paxton’s Flower Garden.
Currently there are four varieties recognized by the World List of Plant Families, as follows:
- Dendrobium bigibbum var. bigibbum, which has a central white area on the labellum, and lives at low altitudes on the Cape York peninsula, some of the Torres Strait Islands, and southern New Guinea;
- Dendrobium bigibbum var. compactum, (C.T.White), Peter B.Adams, a lithophilic variety with a restricted distribution at altitudes of 250 m, in tropical wet areas;
- Dendrobium bigibbum var. schoederianum (Rchb.f. ex W.Watson), which shows color variability and populates only the Larat Islands in the Tanimbar island group;
- Dendrobium bigibbum var. superbum, Rchb.f., which has the largest flowers among all varieties of Dendrobium biggibum, but lacks the central white spot on the labellum and populates the area between Cooktown and Mount Molloy.
Dendrobium biggibum is the floral emblem of the Australian state of Queensland. In terms of conservation and protection status, Dendrobium biggibum is listed as a vulnerable species under the Environment Protection and Biodiversity Conservation Act 1999 issued by the Australian Government. The main threats identified for this species are considered to be human settlements and pressures from visitors, such as fire in unmanaged areas and illegal collection.
The known synonyms for this species are: Callista bigibba, Callista phalaenopsis, Callista sumneri, Dendrobium bigibbum f. compactum, Dendrobium bigibbum f. phalaenopsis, Dendrobium bigibbum f. superbium, Dendrobium bigibbum subvar candidum, Dendrobium bigibbum subvar. compactum, Dendrobium bigibbum subvar. superbum, Dendrobium bigibbum var. albopurpuratum, Dendrobium bigibbum var. album, Dendrobium bigibbum var candidum, Dendrobium bigibbum var. macranthum, Dendrobium bigibbum var. phalaenopsis, Dendrobium bigibbum var sumneri, Dendrobium bigibbum var. superbum, Dendrobium lithocola, Dendrobium phalaenopsis, Dendrobium phalaenopsis var. albopurpureum, Dendrobium phalaenopsis var. album, Dendrobium phalaenopsis var. album, Dendrobium phalaenopsis var. chamberlainianum, Dendrobium phalaenopsis var. compactum, Dendrobium phalaenopsis var. dellense, Dendrobium phalaenopsis var. highburyense, Dendrobium phalaenopsis var. hololeuca, Dendrobium phalaenopsis var. lindeniae, Dendrobium phalaenopsis var. rothschildianum, Dendrobium phalaenopsis var. rubescens, Dendrobium phalaenopsis var. schroderianum, Dendrobium phalaenopsis var. schroederianum, Dendrobium phalaenopsis var. splendens, Dendrobium phalaenopsis var. statterianum, Dendrobium phalaenopsis var. thundersleyense, Dendrobium sumneri, Vappodes bigibba, Vappodes lithocola, Vappodes phalaenopsis.
Epiphytic or lithophilic species, with green or sometimes purplish pseudobulbs, with lengths that can vary from 20 to 120 cm and 1.5 – 2 cm thickness, often with purplish growths. Each pseudobulb has between 3 and 5 ovate leaves, 10 – 15 cm long and 3 – 3.5 cm wide. The flower stalks, arcuate, 20 – 40 cm long, bear between 2 and 20 flowers, generally lilac – purple in color, rarely blue or pink. The resupinate flowers, approximately 2 – 3 cm long and 3 – 7 cm wide, whose dimensions vary depending on the variety, have oblong to ovate sepals, 2 – 3 cm long and 0.9 – 1.1 cm wide. The dorsal sepal is erect or curved backward, while the lateral ones are positioned opposite. The petals are ovoid in shape, with length and width approximately equal, varying between 2.5 – 30 cm, and the labellum, 2 – 2.6 cm long and 2 – 2.8 cm wide, is trilobed. The lateral lobes are erect, and the central one has 4 – 5 longitudinally arranged ridges, as well as a hairy area in the central position. The species blooms from February to July, but horticultural hybrids can bloom abundantly in any season, several times a year, depending on environmental conditions.
This species survives in low light areas during winter, but this aspect leads to the abortion of buds and underdeveloped flower stalks.
From the point of view of light radiation, Dendrobium biggibum prefers levels of 30000 – 45000 lux, with more intense light during the winter period. High values of light variation and good ventilation are decisive aspects in the successful cultivation of this species. In the short term (up to a few weeks), the plant withstands very well in conditions of very low light radiation.
The plants love warmth, preferring 29 – 30 ℃ during the day and 20 - 22 ℃ at night, for the summer period, and 24 – 26 ℃ during the day with 17 – 19 ℃ at night, during the winter period. Bigibbum can thus be successfully cultivated outdoors during the warm season, ensuring a humidity of 60 – 80% correlated with the ambient temperature.
Although this orchid can be easily grown mounted on wooden plaques, cork, or bark, the high humidity preferences, especially during the warm period, indicate that culture in perforated pots with efficient drainage, on a substrate made of small/medium grain pine bark, or specific mixtures, should be preferred. If mounting on plaques is chosen, it is recommended to use a "ball" of sphagnum in the root area for better moisture retention. Repotting will be done during the resting period, towards the end of winter - beginning of spring.
Irrigations will be generous in the warm season, but reduced in winter. Dendrobium bigibbum tolerates very well the lack of humidity in the short term, which allows the safe transport of plants over long distances.
Fertilizations can be done weekly at concentrations of 25% - 50% compared to the values indicated by the manufacturer on the packaging, preferring a fertilizer with a higher nitrogen content for the growth period, from the beginning until almost the end of summer, and a fertilizer rich in phosphorus from the end of summer until autumn.
The resting period actually represents only a reduction in watering for a few weeks, after the flowering period. The substrate will be allowed to dry completely between waterings, but it is recommended to spray the leaves with water and maintain a high atmospheric humidity.
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