Few years ago, someone planted bunch of Bletilla striata in the front yard of the office. They do grow like weeds in here. In fact, there were too many of them so that the management had to pull out nearly two third of them to make room for other flowers.
I bought mine one and a hal year ago. I had 4 growths last spring and now I have 7 new growths. It's a growing rate of 75% which is good.
I have them in a clay pot sitting outdoors whole year. I never water it during rest time. It is more or less protected from rain except when the wind is coming from North or West, which is almost always in winter. So it gets occasional water bit they never get soaked.
I have some growing in pots (or actually, wide bulb pans) and some in the ground. For what it's worth, the ones in the ground seem to grow better and bloom sooner. (My soil in the ground is awful clay, they don't seem to mind) They get water all year, since I don't isolate them. Right now, the ones in the ground are ablaze, the ones in pots just putting up new growth. I guess that just means that I will have Bletilla striata flowers for a longer time. Not complaining!