Saturday, November 1, 2008
One of the problems that you find when you are helping new orchid growers deal with problems regarding their plants is that for some themes there is hardly any information or photos posted. You can find thousands of stunning flower photos but few showing how a healthy root system should look like. To ameliorate this problem I am posting some pictures of how a healthy root system of an evergreen dendrobium of the group of hybrids of sphatulata x phalaenanthe sections. Along with some tips on keeping the roots alive and growing.As you look at the photo please note the following details.
1. There is very little by the way of organic material, the plant is potted in marble chips and the mix is quite clean, no moss, sphagnum or other moisture retentive material.
2. The mix is dry but you see massive root growth.
3. The roots are white and the growing tips are green and all growing at the same time, this is a sign of uniform cultural practices. You see very few dead roots.
4. The mix is firmly but not heavily packed, it has lots of empty spaces but the plant doesn't wiggle in the pot.
5. The bulk of the root mass is attached to the pot not to the mix.The paramount need of these types of dendrobiums is that the roots have access to ventilation and that they experience a cycle of drying. Nothing kills this plants better than tyranny of the evenlymoistness. When watering these plants they need to be thoroughly soaked, drenched even, but then they have to be allowed to dry. Heavy packed mix+heavy watering hand=root death. They need fertilizer but in mild concentrations and frequent applications, root killing high fertilizer concentrations on irregular intervals are sure death.
These flies are usually quite wary as in the garden there are a plethora of predators that think of flies as convenience food. However it seems the smell of this Bulbophyllum biflorum had them entranced to such a degree that they would not move from the flower even when I approached very closely. When I shooed one away the other one would quickly jump on the flower. When both landed on the flower a scuffle ensued and one was thrown from the flower. I could not help but think of two gunslingers that were waiting to see who would make the first move. I have tried to detect a smell but it I can't smell anything. Perhaps other people who have this plant can describe the smell. I assume it is a fecal smell due to the type of fly that is attracted to the flower. Even though ordinarily I would shoo the flies away as to prevent them removing the pollen and causing premature folding of the flowers, in this case I am going to allow the poor blighters some leeway. The truth is that the life of these flies must be one big and smelly pile of s**t, so if they are trying to get their jollies in much pleasanter surroundings I will not be the one to deprive them of the opportunity.