I have just launched a webcam staring my six-foot cactus, Baby. http://governmentcheese.ca/cactuscam/ Trouble is I don't know what kind of cactus I have! Any suggestions would be greatly appreciated...
A Google Images search has proven you right - I am the proud owner of an African Milk Tree, also commonly known as a Cathedral Cactus (even though it is technically not a cactus).
Example of convergent evolution, that is completely unrelated plants having similar forms because of similar habitats.
My Cathedral Cactus is over 7 feet tall. I used to put it in the shower to get the dust off it; however, it's much too heavy and too tall to do that any more. Can anyone tell me how to keep the dust off the plant other than laying plastic around the surroundings and spray it with clear water? This is really a task, but I'm afraid dust on it will eventually smother the plant. Taking it outside and spraying it with the hose is not an option either.
Compressed air? Like one of those cans you get an office supply store to clean of electronic equipment.
