Cymbidium erythrostylum

by Joshua White

A typical example of the species.

Cymbidium erythrostylum is one of the jewels of the genus. It was discovered in Vietnam in 1891 by Wilhelm Micholitz and made its way into the Royal Botanic Gardens at Glasnevin, where it was formally described by Robert Allan Wolfe in 1905. Numerous awards followed over the years, with three different clones awarded in Australia between 1999 and 2009 (‘Magnificum’ HCC/OSCOV, ‘Kennedy’ HCC/OSCOV and ‘Dale’ HCC/OSCOV).

It is one of the large-flowered species and produces delicate, crystalline white blooms with a yellow lip marked in varying shades of pink, purple or red. Unfortunately, these are easily damaged and are susceptible to Botrytis, traits which are readily passed to its progeny. Unlike most of the other large-flowered species, the petals are drawn forward over the column, giving the flower a triangular shape. Additionally, the tepal width is greater than many other species and this can produce relatively full flowers in the offspring.

The flowers are presented on an arching spike and usually number between 5 and 8 per spike, although exceptional forms have been known to produce 12. Flowers last between 4 and 6 weeks, depending on the clone and the conditions. The flowers do not last if the spike is cut, making it and its immediate offspring unsuitable for cut flowers. Like Cym. tracyanum, spikes are produced on the maturing growth (i.e., before the pseudobulb has fully formed), and it can produce two spikes per bulb when grown well. The species does not rebloom on the mature bulb, although this trait can be overcome when suitably partnered (such as in Cym. Frosty Jack, the hybrid with Cym. mastersii).

In Australia, peak flowering occurs during April and May, although in some cases it can flower as early as March or as late as August. It is unusual in that its flowering season in cultivation differs to that in nature (late spring and early summer); this difference is thought to result from the distinct wet and dry seasons in its native habitat.

In the past decade, an alba form of the species has been propagated. Selfings of two different clones have been made available in Australia over the past few years – ‘Blumen Insel’ CBM/JOGA and ‘Tokyo Fantasy’. To the best of my knowledge, there has been no attempt to produce a 4n alba thus far.

The first 4n strain of the regular form was produced in the mid-1980s by Andy Easton, the best of which was the awarded ‘Tikitere’ 4n. It was selfed and the seedlings distributed around the world, giving rise to many of the tetraploids in circulation today. To date, Andy still considers this the finest form of the species he has seen.

It is thought that many plants of the regular form in Australia originate from a single strain. There has also been some confusion over the ploidy of available plants. It has been suggested that most examples of the species in circulation are 4n, but apart from the alba selfings mentioned above, Cym. erythrostylum ‘Royale’ is also known to be a diploid. ‘Magnificum’ predates the 4n strain, ‘Dale’ is thought to be 4n and the ploidy of ‘Springfield’ appears to be 4n (from stomatal guard cell measurements), although Nado reports it breeds like a 2n.

The species is quite compact, especially considering the flower size. The foliage is fine and clean but can be easily suffer windburn (moderate to strong winds coupled with low humidity can lead to significant damage to the bulbs and leaves). This tenderness is often passed onto its progeny as well.

Cultivation

The species is usually found as an epiphyte but will also grow as a lithophyte or even terrestrially where excellent drainage is available. It will grow in a similar mix to many other Cym species and should be kept under cover and on the dry side during winter (watering no more than once a fortnight), protected from rain, frosts, and low humidity. Too much water during winter causes the root system to deteriorate and sets the plant back.

During summer it needs to be under shade cloth to avoid sunburn or limited to mid-morning sun only. For additional cultural information, extensive notes on the species have been produced by Charles and Margaret Baker and are freely available at https://orchidculture.com/COD/FREE/FS295.html.

This is an excerpt of an article that first appeared in Cymbidium Chatter Issue 30 (April 2021) and was last revised 6th June 2023. Back issues of Cymbidium Chatter are available here.