I just got a Dendrobium, it is Dendrobium eima x impact. The
flowers are pink and white. I was wondering how I can tell if it is a
deciduous one or an evergreen one. I still have months before winter,
but want to make sure I give it the rest it needs when the winter does
get here.
There are deciduous and evergreen types of Dendrobium. Unfortunately, I could not find information about the variety you are growing. If yours has soft canes, it is deciduous; hard canes are characteristic of the evergreen type. Here is information from Orchids Made Easy:
“Dendrobiums are separated into two main groups: hard-caned and soft-caned.
Hard-caned Dendrobiums have tall pseudobulbs that are very thin and their leaves are generally a little darker in color than the soft-caned. Hard-caned Dens are evergreen and often keep their leaves for many years before they drop them. Hard-caned Dens grow spikes from the top of the cane and produce gorgeous flower sprays.
“Soft-caned Dendrobiums have leafy pseudobulbs that are long and slim. Their leaves are generally a little lighter in color than the hard-caned Dens. They grow leaves along the length of the cane and the blooms sprout from the individual stems that are along the cane itself. Soft-caned dendrobiums are deciduous and drop their leaves
when the weather gets cold.”
The American Orchid Society has a guide to growing evergreen Dendrobium for beginners.
There is also good general information on caring for orchids in the Brooklyn Botanic Garden guides on the subject. Generally, winter is the time to hold back on watering a bit, but also be careful about the plant’s need for humidity–our heated homes in winter can be exceedingly dry. According to Orchids by Joyce Stewart (Timber Press, 2000), most orchids prefer 65-75% humidity during the day. She recommends “damping down last thing at night” during the winter (using a spray bottle or mister), if you have heat on in your house overnight.