Phiaus – A terrestrial Orchid
Orchids most commonly raised by hobbyist are epiphyte, i.e., they grow on tree branches and derive their moisture and nutrients from the air and rain .. There are many families of terrestrial orchids, i.e., plants that grow in the ground. Phiaus are one family of terrestrial orchids. They can grow large and have brightly colored flowers. The Nun's Orchid, Phiaus tankerville, is beautiful in its own right and the parent of many hybrids. Gastrophaius Dan Rosenberg, Phiaus Joan Hart and Gastrophaius Micro Burst are some hybrids of Phiaus tankerville.
Care of these orchids is easy, but a little extra attention to their needs will increase their beauty. They like light but avoid direct light, a bright but shady area is best. They like a lot of water but not wet feet. They do best in a perennial garden with daily watering and good drainage. They can easily get to 3-4 feet tall and multiple spikes of 10-20 flowers each. 
When the flowers fade they require a little special treatment. As new growth begins to emerge and you remove the dead flower stalks, you should not stop but remove all the old growth. Wait until the new growth is about six inches high and cut off all the old growth, even if the leaves look good.
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The old growth will never flower again. All the flowers will come from the new growth.
The Phiaus in the middle looks good but really needs to be cut off. The two on the sides have been cut about six weeks before the photo for comparison.
The photo on the right shows what is new growth and what needs to be cut. The old growth is where the flowers grew this year. The two dark bulges in the middle are last years growth that was cut allowing this years growth to mature.
We cut the old growth just above the pseudobulb.
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Added 8/8/2014 Cutting off all the old growth is the commercial method of growing Phiaus. We have realized that it is confusing for hobbyist and not necessary for beautiful home grown plants.
The leaves can get to look quite bad. That is why it is cut off for sale reasons. Easier for the hobbyist is to cut off any "leaf", that looks bad (badly damaged leaves do not produce food for the plant, while taking strength out of the plant). Good looking leaves are producing food for the plant and can be left on.
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Photo on right shows three old growths removed
The plant can be grown like this or it is a good time to separate the plant into several new pots. This plant can be divided in half or four separate plants.
For some additional fun try propagating your Phiaus from flower stem cuttings. It is one of the few orchids that will reproduce this way. It is not practical on a commercial scale as seldom do you get more than 10-15% to root. But this is your hobby and if you think it will be fun to try go for it.
Just take the flower stems and cut it into pieces with a viable node in each cutting. Place them on a moist bed of sphagnum or damp sand and see what happens.
By removing the old growth, it allows the plant to put all its energy into the new growth.
Compare how much faster the plants grow when the old growth is removed.
The plant we just cut is in the middle and the ones cut six weeks ago are on the sides. The growth rate on the previously cut plants is almost double the one we just cut.
Plants grown in the ground rather than in pots should have the old growth removed in the same manner. Failure to remove them will stress the plant and it will slowly deteriorate over a couple of years. Since it takes a couple of years to die, it is not easy to understand why it dies and how it could be prevented.