by Lia Andrews
As a Chinese Medicine doctor I have a special connection with this group of orchids. In Chinese dendrobiums are called Shí Hú 石斛 (literally “rock herb” ) due to the habit of growing on limestone in the wild. These orchids evolved to withstand the feast or famine climate extremes in their natural environment by building substantial energy stores in their pseudobulbs (canes or stalks); energy stores which are also highly beneficial to humans. Medicinally there are some 20+ species in the soft cane and callista subcategories used as a general longevity tonic as well as for fever, poor eyesight, dryness, and tendon/ligament weakness. They also produce some of the most stunning flowers in the orchid world.
Dendrobium is a huge genus spanning much of Asia with 6 major subgroups: phalaenanthe, spatulata, dendrobium (deciduous or soft cane), latouria, and formosae. John is the premiere, award-winning soft cane dendrobium grower in Florida. This special subgroup include: nobile, aphyllum, fimbriatum, loddigesii, anosmum, etc. John’s talk was specific to dendrobium nobile and its hybrids, but can be applied to other deciduous dendrobiums. The predominant theme of John’s talk was that success with this group means replicating the extremes in which they thrive; what many of us who coddle our orchids would call borderline abuse.
Nobile dendrobiums are native to a wide geographic area that encompasses the Chinese Himalayas, Assam, Eastern Himalayas, India, Nepal, Bhutan, Myanmar, Thailand, Laos and Vietnam. They have adapted to growing on trees, rocks (limestone), and the ground, and to cool and warm climates.
Hawaiian grower Yamamoto is the leading hybridizer of nobile dendrobiums. Properly grown, these provide 2-3 months of blooms in the winter to spring. John recommends finding out the natural growing condition of their parentage (as with any hybrid). Below is an example of the parentage of Dendrobium Oriental Sile ‘Fantasy’:
REPLICATING WET/DRY SEASON
The wet season in the native environment is three times wetter than Florida (which seems inconceivable for those of us who live here). Yamamoto’s nursery waters their nobile dendrobiums three times a day during the growing season. John is a hobbiest, and like most of us, has a day job. His way of maximizing water intake is to grow in sphagnum moss. This is usually the surest way to rot an orchid’s roots in Florida, but John assured us in his many years of growing he’s had few problems, and if there looks to be an issue, he simply sprays a little peroxide. John leaves his nobiles out in the elements. During the rainy season the nobiles are growing rigorously and absorbing water at a fast pace. During the dry season the moss will dry out like a brick and repel water, ensuring a thorough drying out season.
During the Spring and Summer water daily. During the winter rest period completely ignore them. At most, John will wash off the undersides of the leaves with a strong jet of water to kill spider mites (the primary pest that attacks during the dry winter months).
I’ve learned from observing successful growers is that their practices balance each other out. This is true of John. He gets away with growing in moss because of his potting practices and light levels.
John recommends soaking the entire brick of high quality sphagnum moss in water to loosen it before breaking it into pieces. If you break up sphagnum when it is dry you are speeding up the decomposition process of the moss. He then packs the orchid with moss snuggly in a small plastic pot (no styrofoam or fillers). John repotts about every 4 years. Of all the orchids, dendrobiums really like to be underpotted.
GROW IN FULL SUN
John attributes his success largely to this. He grows his deciduous dendrobiums in as high a light as they can handle. For nobiles, this means full sun. (John also grows his callista and phalaenopsis-type dendrobiums in full sun). He says not to worry about burning the leaves. The old leaves may get a little singed, but the newer leaves acclimate. They will drop its leaves in the winter anyways. Growing in too little light leads to tiny stalks. If mounting in trees, select one with a thin canopy such as a ponciana or jacaranda
John uses a time-release fertilizer he purchases from Broward Orchid Supply once a year shortly after he reintroduces watering in the spring. Do not use Osmocote in Florida as it degrades too quickly. John does not focus on feeding.
WELL-TIMED COLD SPELL
Florida has the same wet summer, dry winter climate. What Florida does not have is the elevation, meaning coolness is lacking. In a “cold” winter getting down to the low 40s and 30s triggers deciduous dendrobiums to flower fully once the weather warms. In warm winters John recommends a short time in the refrigerator. For one week, place in the refrigerator overnight and place outside during the day. This is especially effective for cooler growers like Dendrobium loddigesii. (Dendrobium moniliforme is difficult to grow in Florida because it cannot handle the heat).
John systematically fattens up those pseudobulbs to the max with sun and water, and to a lesser extent, food.
John Romano’s deciduous dendrobium equation (also works for castaceums):
Full sun + lots of water (growing season) + moss
Spring: once buds are full delineated, slowly reintroduce water
Labor Day: stop feeding
Thanksgiving: stop watering
OBSERVING YOUR NOBILE DENDROBIUMS
A more individualized approach is to observe each orchid as they will mature at different rate. Ones that mature faster, will go into dormancy earlier in the fall and will flower earlier in late winter/spring. Water daily until the pseudobulb stops pushing out new leaves:
Start watering only when see individuated flower buds
John Romano, LMT
Let’s Talk Orchids