These plants get HUGE in warm climates, and being covered with spines you don't want to bump into them. So if they're planted in the ground, make sure they are nowhere near structures, paths, driveways, sidewalks, and so on. Furthermore, they have a tendency to lose branches from them getting too heavy, and that's a pain to deal with because branches and trunks are not only extremely heavy, they're covered with long spines.
