Plants in general bring positive Feng Shui in your home. But cacti are somewhat specific. There is no denying that they are nice plants with strong protective energy. In fact, they emit Yin energy (water) that is accumulated inside their succulent body.

The problem, however, is in their needles. As sharp objects they look like thousands of tiny arrows that shoot directed energy into the surrounding space. That’s why good placement of cacti is important according to Feng Shui.

What’s wrong with placing cactus plant in the living room?

A living room that has good Feng shui is a calm and secluded place where you can feel comfortable, rest and relax. If you have your cactus plants all over the place, they will constantly poke you with their sharp pointed tips.
Unless your fame and reputation quadrant is in your living room (see image) you shouldn’t have them there.
In order to bring good Feng shui, the cactus has to go in the fame and reputation quadrant. The fame and reputation quadrant is the part of your home dedicated to what and who you are and what you want to bring to the outside world. In Feng shui, the fame and reputation corner corresponds to the fire element. Colors present in this quadrant should be bright and fiery, for example, orange, yellow or red.
When you put your cactus plants there, symbolically you work on protecting your career and reputation. The “fame and reputation” corner of your home is directly across as seen from the main entrance.

Summary:

Cactus plants can have subtle beauty and bring fulfilling visual experience especially when they produce flowers. If you love to have them in your home, ensure that they have a proper placement.

The only safe position for a cactus plant in your home is the fame and reputation quadrant. Make sure they are NOT positioned in your kitchen, bedroom, dining room, office, or other prohibited areas. Otherwise they may affect your life in a more direct way than you may be willing to admit.