Whenever I teach plant identification and we are outside looking at plants, if there is some sort of cactus nearby, someone, somehow or some way, either steps in it or trips right over it.

Cacti, yucca and agaves make great drought tolerant additions to landscapes, but one has to be careful about how close to a sidewalk one plants them. If it’s too close, I can guarantee that someone, some way, will manage to get into it with unpleasant consequences.

Some cacti are safer than others. An example ...