Good things come to those who wait we are told. Helleborus vesicarius seedlings were set out in spring of 2006 after a supplier donated a pot full of 20 seedlings with the warning that it was a very tricky species to grow. He was in Virginia, not exactly a similar climate to southern Turkey and northern Syria where it is native. Denver is perhaps not an exact match either, but closer with summer drought broken only by sporadic thunderstorms.
Originating from montane elevations in alkaline clay soils, it has so far been hardier than predicated. "Hellebores: a Comprehensive Guide" by C. Colston Burrel and Juduth Knot Tyler guessed zone 7. It has survived -10 degrees Fahrenheit with almost no snow cover on several nights. Its high elevation home no doubt instilled some cold hardiness and probable tolerance to some summer moisture in semi-arid climates.
H. vesicarius is unique in the genus Helleborus in that it has both basal leaves as well as true stem leaves, and unlike the more commonly grown Helleborus x hybridus, H. niger, or even H. foetidus it goes dormant for the summer and apparently needs a dry summer rest otherwise it rots. One more "uncoventonal" feature is that like many plants native to Mediterranean climates it starts growth in the fall and grows slowly through the winter, speeding up with the lengthening days.
It may not be the showiest in flower, but the seed pods are the main attraction. We will see if it sets seed pods with only one out of the three surviving plants blooming this year.
Helleborus vesicarius can be found in the Woodland Garden bed at the north end of the Rock Alpine Garden. Look under the south side of the largest boulder beneath the western river birch. The flowers should fully open in a few days or several weeks depending on how cold it stays.