House Plants/Madagascar Palm
About five years ago some friends gave us a large MP about 10 feet tall. It has been fine and is now 11 feet tall. I had read that MP's should be watered less in the summer and more in the winter because their native land's weather cycles and opposite ours. This summer I watered infrequently. My husband decided it needed more water and went overboard I think. All the leaves have dropped. How do I know if it is alive? Should I water or wait to water until I see some growth?
If you are going to treat it as though it is still in the southern hemisphere you need to be giving it extra light to lengthen the days in the winter and drawing the shades to imitate the shorter days of winter. Actually the Pachypodium lamerei adapts quite well to living in the northern hemisphere so your husband was right it does need more water in the summer. However you did not discuss sun exposure. This plant prefers full sun. I note that you live in New Mexico. You did not state whether it is growing outdoors in the ground or indoors in a large pot. If it is indoors it is only getting sun from 1 or 2 sides at the most. Preferrably it is sitting in a southwest corner with windows on both sides and no window coverings.
Water your Madagascar palm tree sparingly. Only water it in summer when the top third or so of the soil has dried out,you can tell this by inserting a bamboo skewer into the soil and leave it there. Pull it out when you think the plant is dry and the skewer will tell you if the top third of soil is dry. Then water the plant until the soil is moist. In winter, when the Madagascar palm sheds its leaves and goes dormant, stop watering it altogether until spring.
Fertilize your Madagascar palm once in the spring if you want to encourage it to grow quickly. Use a balanced liquid commercial fertilizer like Peter's Professional or Miracle Grow. Look at the package directions for application amounts and divide that amount by half.
If you have more questions feel free to write again. Good luck!