Intro: Also called touch-me-not and many other common names, the sensitive plant (Mimosa pudica) is from South America and southern Central America. Mimosa pudica is a fascinating plant to keep in a balcony garden because it can move. Like the more famous Venus fly traps, the sensitive plant responds to touch.
Unlike the Venus flytrap, the sensitive plant closes its leaves to protect itself. It is not a carnivorous garden plant and does not move to trap insects to digest. If you touch, shake or blow on this container plant, the leaves will fold quickly and reopen in a few minutes. When the sensitive plant is disturbed, the plant forces water out of its cells, which results in cell collapse (which we see as closed leaves). When one leaf closes, it can stimulate neighboring leaves to also close.
Mimosa pudica can grow up to 5 feet high and 3 feet wide, although it will normally only grow 1 foot to 3 feet tall in the garden. The sensitive plant blooms with pink globular flowers about an inch across from mid- to late summer. Plant your sensitive plant in peat moss and perlite (ratio of 1:1 or 2:1). You can also use loam and sand, respectively, in your container garden.
Scientific Name: Mimosa pudica
Plant Type: Although it somewhat resembles a fern, the sensitive plant is a creeping annual herb.
Light: Partial shade to full sun for at least eight hours each day. The sensitive plant's leaves will close if it does not receive enough light (leaves will also close at night).
Water: When it comes to watering, provide consistently moist potting soil but never let it get soggy.
Zone: Keep the sensitive plant outside only in Zone 11. Can be kept as an outdoor plant in the tropics, but it’s best kept as a houseplant in indoor gardens in most areas. Never let the sensitive plant get colder than 65 degrees, or else its leaves and stems will turn yellow.
Fertilizer: Give the sensitive plant half-strength fertilizer weekly during the growing season.
Pests and Diseases: This hardy plant should not be bothered by garden pests or disease.
Propagation: The sensitive plant is most often grown from seeds. Pink flowers produce seeds. Sow the seeds in moist peat moss and perlite, and place clear plastic above the planting medium, as seeds need a lot of moisture to sprout. Expect the seeds to sprout in 14 to 21 days. You can also propagate Mimosa pudica by taking cuttings. Cut a branch that has one leaf node and plant it in the peat moss and perlite planting medium. Place a plastic bag or plastic wrap over the top of the sensitive plant and the plant container in order to keep the air around the plant humid.
Misc. Info: It is unknown exactly why Mimosa pudica has evolved to close its leaves. It could serve as protection from predators that may eat it, from harsh weather, destructive garden pests, etc.
The sensitive plant has been introduced to other areas and has become an invasive weed in Australia, Hawaii and other places.
The species name pudica is Latin for "bashful" in reference to the sensitive plant's closing leaves after being touched.