Question
My husband has has this cactus for years. Abot two years ago it started what looks like a new one growing from the top. I'm sorry I'm not sure what type it is. I looked online and think it might be something like a mexican fence post or a peruvian torch, but we were wondering if we took the new growth from the top if either plant would survive. the total height if 6ft and with the pot it almost touches the ceiling in our house.

Answer
Dear Mary,

Do you mean it is growing a new offshoot or arm?  You certainly can remove the new growth by cutting it off with a sharp, sterilized (with rubbing alcohol) knife.  Make a clean cut.  If you need to make more than one cut, sterilize the knife before each cut.  I then brush the cut with a fungicide powder, or if you don't have that you can use a root starting powder such as rootone, just to make sure no bacteria or fungus enters the wound. If you don't have either the cactus will still callous over at the site. (I'm a tad obsessive).  You can also root the cutting if you like.  Let it callous over first. Even if the new growth is coming directly out of the top of the plant you can remove it in the same way.  It may leave a larger callous if it's a large growth.

If you have a photo, I may be able to tell you what you have, tho no guarantees.

So cut away,

Maureen