Daniel_B wrote:
Hello, I live in the midwest, IL., USA. I was visiting my brother and
his family today and noticed a very strange plant I have never seen
before growing in one of their outside flower pots. I asked my sister
in-law about it and she said it just startd growing a couple of weeks
ago and she decided not to pull it out. My other brother who was also
there and is an avid gardener said he had never seen this type of plant
either. The plant is about a foot high now. It has lots of stems with
leaves that, when the sun is on them, open up. When I saw it, the plant
was in shade and the leaves were folded up, kind of like a zipper. Each
leaf is about a 1/4 inch length. The whole plant is the same color of
green. I would say about the same shade of green as a tomatoe plant
leaf.
Looks like something that would grow in a rain forest.
I wanted to do a google search on it, but where to start?
Thanks for any info.
Dan.


There are two completely different plants that are commonly known as
"mimosa," and it's probably one or the other. Mimosa pudica is a
tropical plant native to south america that's often grown as a curiosity
ornamental, but I don't know if it would naturalize as a weed in
Illinois. This type of mimosa folds up when touched.

The other, Albizia julibrissin, known as mimosa or silk tree, is native
to Japan but is hardy to zone 6 and has naturalized around much of the
mid-atlantic and southern US. It grows very quickly, spreads easily, and
has big fluffy pink flowers in June. This type of mimosa folds up in the
evening, but are not as responsive to touch, in my experience.