Sleeping Grass
Key: R20100418-112441
Key: R20100418-112504
This post is not for photographic interest, but purely botanical interest. I thought some of my readers may be interested in finding out about this curious plant, which was unknown to me prior to taking up residence in Hawaii. I assume this may grow in other temperate areas, so perhaps it is more widely recognized than I suppose. Here it is primarily referred to as Sleeping Grass, although it is also known as Mimosa.
The plant gets its name from the fact that, when disturbed, the leaves “wilt” and fold up rapidly as though protecting itself. Note the before and after pictures here: in the second frame I had just a moment before run my hand over the leaves. Over the course of a hour or so they will unfold and spread out again.
Although the leaves are soft, the stems are spiny with sharp thorns and barbs. Though small, they are painful if you grasp it in the wrong way or step on it with a sensitive part of a bare foot. This, combined with the fact that it grows so rapidly and voraciously, means that it is mostly considered a nuisance plant. I am constantly pulling it out of the yard. It grows a small, delicate purple flower.
Red Skies at Night 
Eric, That’s a new one for me — I don’t remember ever hearing of it before. Something new I’ve learned today. Thanks!
Among various ferns growing here, I had been hoping to find it. Hope I had abandoned, and left an encounter to chance. Eric, thanks for the visual clue as it would save be from running my hand over every stem.
After a search on “mimosa”, realized that the plant in question is likely Mimosa pudica (have known it as “touch-me-not” in English, “chui mui” in Hindi). And, it is not a fern, but leaves look like that of a fern.
The More Your Know.
@Earl, you are welcome!
@Parv, you are welcome! I’m surprised you haven’t run into it yet, it’s everywhere!
I really had to study the two images to understand the differences, the retraction of the leaves is very dramatic. Like Earl, I’ve never heard of such a plant and probably never seen one. I’ve learned something new today, thanks!
Hi Monte,
You inspired me to make a video to illustrate the behavior more clearly. Hope it helps!
I am curious to it’s relationship to the Mimosa tree I grew up with in the states.
Hi Darlene,
There is another tree that grows here called the Mimosa, but it is a real tree, not a weed like this. It is a rather striking tree, with beautiful flowers.