Though what’s shown here may not be indigenous, Bhutan has a wide variety of plants growing in the country. Here is some of the blooming kind.
http://www.bhutan2008.bt/en/node/276
Our family friend, Mr. Nishioka, had a book (now out of print) on Bhutanese flowers:
And I am wondering if this is cannabis which is widely used in decorating traditional Bhutanese paper (I have actually seen this) and feeding pigs (so I read). The way the leaves branch out looks slightly different so maybe not.