*edit* Don't forget the cactus is broken into three sections so you can't dupe the whole thing, you have to dupe piece by piece.
Or build it on a 2x6 plate and duplicate that into the brick below it (which will only duplicate the cactus), it's more efficient.
Ever heard of a brain?
Try using yours, they're free and useful.
forget off. My point is still valid.
Unless you have a desert the size of the walkable area of Slate, no it's not.
The brick limit is quite high and having even several hundred cacti at around 14 bricks a piece is only going to cost about 1400 bricks, which there's plently more bricks after that.