Pachydpodium aka Madagascar palm

[AL]

I have one in north window that is doing quite well over past year and a half-except it gets brown on tips of som fronds--I water once everythree weeks with 1 cup of water-the plant is a little over 2 ft high--any suggestions

[Cereus-validus.......]

No, your plant is not doing well.

You are doing everything wrong.