by Lia Andrews
Some of my favorite orchids are the cascading dendrobiums of the dendrobium, callista, and phalaenopsis sub groups. These display true Fire (startling and fun) and Water (drama and romance) qualities. I began growing orchids last October and I want to share my mistakes so others can avoid them.
Mistake #1: Dendrobium Phalaenopsis Doesn’t Like Cold!
I assumed all dendrobiums could handle the minor cold in southwest Florida. However, this is not true for D. phalaenopsis. These hybrids use plants growing in Australia and Papua New Guinea where temperatures do not get below 50-55° F. I am unclear whether or not I have a Dendrobium biggibum which is even less cold tolerant (min 60°) and looks almost identical.
I left my poor plant outside in the cold this winter (it dipped down to 40°). She lost all her leaves. This year she sent up 1 new shoot and a keiki (from the stress).
I have 2 other D. phalaenopsis that wintered indoors because they were flowering. They have 2-3 new growths and no keikis. However, they have started to lose their leaves on the old stalks anyways. Apparently this is what happens. This plant does not grow into a specimen plant.
Mistake #2: Do Not Allow the Stems of Dendrobium Anosmum to Sunburn or the Stems Will Die
I was very upset to see that one of my favorite plants, a D. anosmum with lovely lavender flowers looked near death. Experts at the Southwest Florida Orchid Society questioned watering, sun, and media, but I couldn’t figure it out. I observed them more intensively and it finally dawned on me what I had done. I mistakenly placed my Dendrobium anosmums in almost full sun this winter because that is what my Dendrobium nobile and lindleyi seemed to like. I then moved them to the area we grow our cattleyas in the spring. The plants flowered but then showed signs of stress. The first picture shows a D. anosmum var. alba I purchased already flowering that I never put in full sun. It has both strong growth from the base and keikis. This is my healthy model.
The second picture shows a lavender variety D. anosmum. All her stems were sunburned. They yellowed, shriveled at the base, and stopped supporting growth at the ends. There is no new growth yet, but a desperate profusion of keikis.
The third picture shows another D. anosmum var. alba (I think they are more rigorous). The stem that was sunburnt dropped its buds and produced keikis. The stem that wasn’t, flowered well and then sprouted new growth from the root close to that stem.
According to culture sheets these also do not like to get below 50°, although that did not affect flowering or health on unburnt stems. I am attempting to rehabilitate my beloved plant. Hopefully this saves other plants out there from the same fate.