Q.My indoor Norfolk pine is about 15 years old and too big
My indoor Norfolk pine is about 15 years old. It’s in a big pot next to a southeast-facing window. I water it every Monday. That’s all I’ve ever done for it, and it has flourished, but now it has reached the ceiling, where its topmost whorl of branches have begun to spread out against the ceiling. Can I prune it by cutting off the top, or will that kill it? I have no knowledge of horticulture — but this plant has done very well on its own, and I don’t want to kill it, nor do I want it reaching out across the ceiling. Can you help?
Here is what I would do if I had such a wonderful plant - I'd cut it back at whatever height I wanted it to be from the ceiling. IF it sends out new leaders, you can cut them off too. Won't hurt the plant at all. Of the few that I've been acquainted with indoors, only one ever got so big it had to be cut back, and it never did grow from the main stem, although the side branches did continue to grow.
You are in a predicament. I've been in the business a L O N G time, and several truths remain. NIP can grow, in nature, to 100' tall. If the central leader is cut or blown out from weather, the tree will send up new leaders. When it sends up new leaders, the plant is usually not symmetrical. IF, you get 3 or more new leaders, the resulting plant can still look 'funny' if the new growth occurs with a high center of gravity. If it gets top heavy, the new leaders will break away from the original trunk. NIP are best propagated by air-layering a central leader or seed. With all that said, you might find this forum interesting: http://forums2.gardenweb.com/forums/load/houseplt/msg102030242998.html
Maybe there would be a large atrium in a business/church/school/hospital/government building that would accept your plant. Just an idea...