Mimosa Pudica, or the "Sensitive Plant" as it is more commonly known, is characterized by two distinct features. The first is the bushy, alien-purple pompom-like flowers it produces and the second is its almost supernatural phenomenon: it closes its leaves and pulls away from you when you touch it. Although sensitive plants are just that - sensitive - in Northern climates, they grow as sidewalk weeds in the Yucatan Peninsula and near the jungles of Belize and Mexico. Imagine my disbelief when this crazy, shy plant - a plant I've killed and re-purchased half a dozen times - turns up in the gravely, cracked sidewalks of Tulum, Mexico. I stopped in my tracks, knealt beside one and gracefully brushed the pad of my fingertip along its fern-like leafy center. Sure enough, it pulled away from my faster than a schoolyard kiss.
It was then that I realized which what was what. The problems I'd been having keeping my sensitive plant alive and green were all in my head. I had thought that, given its name, it was too sensitive for regular houseplant care and so I tended to them all regularly and with vigor. But that's just it. Sensitive plants are anything but. If they can survive monsoon hurrican winds and rain and grow in the gravelly parts of well-trampled sidewalks in Mexico, then they sure as heck can survive the living conditions of my New England home. Perhaps, just a few modifications.
First: Keep the plant away from cold windows and chilly rooms. Instead, try placing your sensitive plant either in a glass terrarium near a heat source, or just in the center of a room under a grow lamp. This way it can have all the sun exposure a tropically inclined plant should need, but without the cold-winter window panes of a Northern climate to destroy its foliage.
Second: NEVER CUT IT BACK OR TRANSPLANT IT WHEN IT IS FLOWERING. There are few faster ways to kill a sensitive plant. Sure, it will grow all crazy like, spreading out wide over the edge of the pot (and beyond). Just don't do it. Remember, these guys grow wild in tropical climates. They like it rough. Keep it alive by letting it be.
Finally: Think back for a moment to your sixth grade geography lesson. Remember when we learned about the rain forests and the infamous rainy season? Well, this is the kind of condition in which a sensitive plant flourishes. Let your sensitive plant dry out completely between waterings. Then, when you do water it, drench it thoroughly, being sure to check for mold on the soil and other signs of root rott. This should send your sensitive plant sky rocketing.
Good luck with your sensitive plant! And remember: don't touch it too much! It pulls away from you for a reason, after all. What that reason is though, I couldn't tell you. Maybe it just doesn't like people. Ciao!