Question
I have 2 outdoor large cacti that are not doing well.  After the
tallest one bloomed it began to yellow, why has this occurred
and what can I do to bring back it's true green color?  The other
has become scaley  on the edge what causes this?

Thanks for your help.

Answer
Dear Naomi,

There could be a few causes of this issue. First I need to be sure you have a cactus and not a succulent...believe it or not, there is a difference. If you can answer a few questions for me, I should be able to give you an answer.

First, are the spines in pairs along the edges of the plant or are there many spines coming out of what look like fuzzy pincusions? Second, are the yellow areas soft to the touch? Third, do the scaly areas peel off easily?

Please answer these questions the best you can. Also, you can email me a picture to [email protected] if you like. That would be very helpful. Thanks!

Sincerely,

Greg