From Longwood Gardens (edited for brevity):
Once considered a myth, these spectacular flowers—which are native to the high elevations of the Himalayan Mountains—reside in the Longwood Conservatory, where they are made to flower every year in March. This cultivar, ‘Lingholm’, produces large flowers that are four-inches in diameter on average. The substantial petals are a mesmerizing deep sky blue color.
Blue-poppies are infrequently cultivated outside their native habitat. Given the right conditions, however, they can thrive in gardens located in the northern regions of the U.S. and Europe.
I am happy I was able to see them while they were here 🙂