Question
I'm an apartment dweller in the city.  I rescued a tall thin cactus from the garbage.  It has triangular faces on each vertical growth, with small leaves that emerge upon watering frequently (they dry and fall off when I don't).  The top has now hit the ceiling and the whole thing is bending because it keeps growing.  Do I cut off the top and put something on it to heal the wound?  If I do cut the top off, how can I root it to start another plant?  Thanks

Answer
Dear Iliad,

Do you have a sibling named Odyssey?

Good on your rescue - I've done the same for an Araucaria.

What you have is likely not a cactus at all, but a member of the succulent euphorbia Family. Most succulent euphorbias have a latex-like sap that sometimes can be very toxic, so be very careful about getting it on or in you.

Cut the desired portion with a clean hygenic knife, dip the cut end in lukewarm water to staunch the latex, and set aside in a cool and dry location. About a week afterwards, set it on some C&S soil, just a thin layer in a pot will do, and surround it with top dressing (gravel, rocks or the like) to support the cutting. Keep it in the same light you have the original plant in, but don't water it. Mist it only until you see definite growth occur, probably in the Spring. You can then repot the cutting to a larger pot.

Hope this helps,

Jeff