Rodger
I haven't been able to obtain D cucullaria ' Pittsburg' , tho I believe it is still grown in North America and is certainly available commercially in Great Britain. I do grow a pink form that Rick Lupp selected I believe from some wild-collected plants; it is as pretty as might be imagined. I believe Rick's source was from eastern US or from the Midwest. Having failed at growing it as a woodlander, I find Dutchman breeches thrive best here in pots treated as a fritillary or crocus and allowed to dry out in the summer. Anemonella thalictroides seems to do best here with the same culture.
Although Dutchman breeches is usually considered to be a plant of the " east " it does occur in Washington in the Columbia River Gorge between Washington and Oregon. Where I have seen it growing wild it certainly must go completely dry in summer. I haven't tried growing these yet but intend to do so.
Jerry John Flintoff
Vashon Island,Washington,USA
Zone 8- modified Mediterranean