Only three species of Paphiopedilum within the subgenus Parvisepalum boast pink flowers – P. delenatii, P. micranthum, and P. vietnamense. P. delenatii has been has been used to make a wide number of primary hybrids with other Paphiopedilum species, and are the focus of this article. All the plants mentioned here I have grown and flowered at my home in southern Japan.
Most species within this subgenus live in northern Vietnam and adjacent areas of China. The exceptions are P. vietnamense which is found in a very small area in the northern mountains of Vietnam, and P. armeniacum, confined to a small area of Yunnan near the Myanmar border. By contrast, P. delenatti is found only along the southern coastline of Vietnam. The upshot is that all in the group can endure colder temperatures in winter, while P. delenatti is a truly tropical plant.
The earlier primary hybrids with P. delenatii were made from the progeny of one famous plant grown by Marcel Lecoufle. In the last 20 years, with the rediscovery of this species in southern Vietnam, its hybrids have become more diverse and available.
One interesting feature of many its hybrids is the tendency of nearly all white flowers resulting, a sort of “bleaching out” of the purple, yellow, and green pigments. A good example of this is P. Armeni White where the yellow pigment of P. armeniacum are virtually lost. The yellow on the staminode of P. delenatii appears on its hybrids as well.
Without further adieu, here are the P. delenatii primary hybrids I’ve grown over the past 7 or so years.
First off is P. Ho Chi Minh (Popow, 2002), a hybrid made with the closely related species, P. vietnamense. The flower is quite large, up to 10 or more centimeters across. My plant opens relatively flat, but then gets more cupped within the first couple days. While many people complain this hybrid’s flower lasts a very short time (some report a week or less), my plant keeps it’s blooms for three weeks on average. It is a annual bloomer for me, but increases its number of growths slowly.
The next three hybrids all show the above mentioned “bleaching effect”. The first is one of my all time favorite Paph hybrids, P. Armeni White (Kubo, 1987), a cross with the pure yellow flowered P. armeniacum. The flower initially is somewhat cupped and creamy yellow, but within a few days bleaches nearly pure white, except the staminode which is yellow and marked with brick red. As the flower matures it also tends to open more and the petals and dorsal sepal become more wavy.
The one plant I have suffered a set back due to poor roots (I didn’t repot it for the first two seasons), but has recovered. It is said to be very vigorous, easily forming clumps. That has not been my experience, but I don’t find it particularly difficult either. In my book this is a must have Paphiopedilum hybrid.
Next up is P. Lynleigh Koopowitz (Paphanatics, 1991), a cross with the green flowered P. malipoense. Again, nearly all the green pigmentation is lost, and the overall white background color is suffused with light pink and the petals have purple striations. In some specimens the dorsal sepal retains a green cast. The staminode is similar to P. malipoense, with a deep burgundy prevailing on the lower half. The flower shape is much like P. malipoense as well, but with less pointed petals. Flowers can range up to 12 centimeters across and are long lasting, up to a month or more.
This plant has been a good grower for me, but seems loath to increase its number of growths. I have two plants and most years at least one will flower, sometimes both. The leaf shape is more like P. malipoense, broad and large.
Finally, a delicate flowering plant, P. Deperle (Marcel Lecoufle, 1980), the hybrid with P. primulinum, a species from Sumatra. There are two color forms of this hybrid, a pink one and a nearly pure white form (called “v. alba” by some). My plants happen to be the white form and flower regularly for me. The flowers are long lasting (a month or more) and come in pairs usually, with occasional growths bearing three. The staminode is green and yellow with a bit of reddish purple towards its tip. The petals are held in a very elegant arc, so that the flower cannot have the flat look many hybridizers seem to favor. They tend to be a bit smaller than the above mentioned hybrids, not more than 8 centimeters across.
P. primulinum being a member of the subgenus Cochlopetalum has a very different flower form and leaf habit than the species of the subgenus Parvisepalum. Not surprisingly, the leaves of P. Deperle, while they retain a mottled color pattern typical of Parvisepalum species, are also more elongated and lighter green than is typical of straight Parvisepalum hybrids. I have found the plant to readily clump.
In my experience members of Parvisepalum can endure quite a bit of cold in winter, even down to freezing (or colder). Fortunately, the hybrids of P. delenatii seem to have retained this ability of resisting cold. In the winter months mine are kept between 5-10 C for 3 months or more to no ill effect. P. Deperle can withstand this treatment as well, but as far as I can tell, doesn’t appreciate it very much. Traditional Japanese houses lack insulation, so they average just a few degrees above the outdoor ambient temperature!
Members of Parvisepalum, with the exception of P. delenatii, appreciate calcium rich substrates since many grow in habitats with limestone near the surface. For this reason some growers like to put dolomite in their Parvisepalum Paph compost. I have not tried this, but the water I use is from a deep well and is quite hard. I imagine that is adequate to keep them happy. More important is to regularly repot them to keep their roots happy. I try to do this every other year. I use a mix of coarse perlite, pine bark, and charcoal. Like other slipper orchids, while in growth all like lots of water, regular fertilizing, and warm temperatures.
Though I cannot say I am an expert at keeping these lovely plants, they have survived the less than perfect conditions in my home with little fuss. My recommendation is that if you like Parvisepalum hybrids, get more than one of each kind to ensure flowering every year.