Question
I have a succulent (I assume it's a cactus?) that has segmented joints, and has a slightly spongy column.  The needles are soft and can be touched without any discomfort, and the tips of the shoots are purplish.  Here is a picture of the plant... http://i34.photobucket.com/albums/d111/daturahoney/SickCactus.jpg

As you can see, half of the plant has fallen over.  We
transplanted it into a new, larger pot yesterday.  It was
doing this a little bit beforehand, but now it is really bad.  Down at the base of the column, the normally green skin has become very pale (almost grey or white) and looks wrinkly.  It doesn't feel any softer than the rest of the cactus usually does.  What's wrong with it?  How can we help it?  BTW - we used a "Cactus" potting soil and immediately watered it after the transplant.  Thanks for your help! :)

Answer
Dear Melissa,

You have a cactus, Austrocylindropuntia subulata f. cristate. The normal form of this plant (Austrocylindropuntia subulata) can get up to 10 feet tall. This form stays smaller and the stems are weaker. If there is no rot present, this may be normal. If the stem has rot present it will be softer and usually darker color. Usually if a cactus turns white, it is from sunburn, which can also damage the plant.

Only water when the soil is dry and keep an eye on the plant. If it is getting any direct sunlight, move it. If the stem gets mushy, remove the plant that is affected from the pot (look like you have 2 plants there). Hopefully, thats not the case. Please write me back if you have any questions, thanks!

Sincerely,

Greg