Note that the sepals and petals are spirally coiled with the tip innermost
Eulophia petersii is a terrestrial orchid belonging to the plant family Orchidaceae. It is found in amongst rocks in thickets in hot dry arid to very arid environments from the Arabian peninsular in the north down the eastern coast of Africa southwards as far as the Limpopo, Mpumalanga and KwaZulu-Natal provinces of South Africa.
Eulophia petersii is an unusual member of the orchid family in that it lives in a harsh environment. Where it has adapted to very arid environments and is among the few orchids genus’s to have evolved a truly desert living species
It is often found growing in acidic sandy soils or in rock outcroppings often in acid soil derived from decaying granite.
Eulophia petersii has many growth forms even within close proximity to one another.
Below I have shown two specimens that are growing next to one another in the sale growing medium one with medium length leaves and pseudo bulbs the other with extremely long leaves and long thin pseudo bulbs.
The leaves of Eulophia petersii are thick, fleshy and very fibrous and have a sharp serrated edge that vary considerably in length from short and broad to very long and narrow.
There are usually two to five leaves per pseudo bulb.
Eulophia petersii from the Weenen area with medium length leaves
The pseudo bulbs are green to yellowish with pronounced ribbing being almost smooth when fully engorged with water and highly ribbed when very dry the vary in length considerably.
Eulophia petersii from the Mapumulo area with extremely long leaves and long thin pseudo bulbs
The form that grows in Yemen on the southern tip of the Arabian peninsular is much smaller and more compact in habit.
The numerous flowers are widely spaced on a branched inflorescence that can be up to over 2 meters in length. The flowers are green with reddish brown markings with a wrinkled white lip with pink markings. There is quite a bit of variability in the colouration of flowers between plants. Often the sepals and petals are circinate, that is spirally coiled with the tip innermost as in the photo above.
Eulophia petersii showing an extensive healthy root system supporting a healthy plant
Eulophia petersii plants consist of clusters of squat, fat green to yellowish stems called pseudo bulbs connected by short rhizomes that bear a small number of succulent, sharp-edged leaves. The plants are evergreen and the leaves can persist for several years, but the actual growth of the plants is highly seasonal.
New pseudo bulbs and foliage are produced in spring and summer, and tall racemes of flowers are produced in mid-summer.
In the winter, the plants are dormant and can withstand long periods without water.
Eulophia petersii is used as a love charm
Growing Eulophia petersii
Eulophia petersii are very easy and rewarding plants to grow provided one follows a few simple rules. They are probably best grown indoors as pot plants in most localities that have high rainfall or very low temperatures. Eulophia petersii are very hardy and take very little time to care for and to produce good results making them an idea pot plant.
My own plants are grown in a mixture of coarse gravel derived from decaying granite, crushed brick, and clean river sand to which I add a small amount of well rotted leaf mould. They also do well in general purpose cactus and succulent mixes.
I grow my plants on a hot north facing windowsill indoors where they get plenty of sun so that I can protect them from the rain and the yellow orchid beetle Lema pectoralis which is a major pest which can badly damage a plant in the blink of an eyelid.
I do not over pot my plants but I do ensure they have enough space to develop a very good extensive root system this essential for good results.
Yellow orchid beetle Lema pectoralis
In summer I only water my plants when the growing medium has completely dried out for a week or so and I see that the pseudo bulbs have wilted a little then I completely soak the plants with water to which I have added a little liquid fertilizer. Never add more fertilizer per litre than the manufacturers recommendations, this has produced very good results for me. At least once a year in the summer I take the plants outdoors and soak them heavily with a hose pipe to flush any accumulated salts out of the growing medium. This can also be done indoors in a bathtub or basin.
In winter I keep my Eulophia petersii very dry I only water them when I see that the pseudo bulbs have shrunk considerably and the two halves of the leaves have started to fold together and then only enough to slightly wet the growing medium, after a day or two I add a little more water until the pseudo bulbs have regained not more than 50% of their full size. This ensures that the plants develop a very large and healthy root system as can be see in the accompanying photograph. I do not soak the plants.
In the spring when new growths appear I slowly increase the amount of water given until the new pseudo bulbs are well developed
Eulophia petersii do not do at all if well if they over watered in particular in winter and do not develop and maintain a good root system. The easiest way to check if your plant is being over watered or not is to gently tip it out of its growing container and to inspect the roots. A healthy well cared for plant will have and abundance healthy white roots with white tips while in active growth with no black marks or rot on them.
Eulophia petersii can be grown outside in the garden if grown in well drained soil and if they can be protected from mole rats and the yellow orchid beetle. When grown outdoors the must be grown in a hot sunny position or the new growths will tend to rot in the rainy season in places such as Durban and the natal coast.
Eulophia petersii has all the attributes of an excellent green roof plant and will no doubt make a very good green roof plant in areas with a suitable climate. I an yet to test Eulophia petersii under the conditions I experience at Mount Moreland but I am confident they will do well as I already have four species of Eulophia that grow under direr conditions that are thriving with no care whatsoever on my own roofs.
Eulophia petersii can easily be propagated by subdivision, which is probably best done at the end of winter when the first growth is noticed, just be careful not to damage the new growth.
Eulophia petersii plants set seed if pollinated, but as with most other orchids the seeds can mostly only successful grown in flasks on a special growing medium under sterile conditions.
I have never tried growing Eulophia petersii seeds in soil as I have successfully done with Eulophia speciosa but with a little experimenting under the correct conditions it is no doubt possible.