Here?s been our experience. This is the third year ?True Blue? has spent in our garden, and it seems quite happy where we planted it: at the top of a stone retaining wall, in well drained rich soil, in a partly sunny spot (4-6 hours a day). Gentiana ‘True Blue’ begins to bloom by mid July and carries on through the summer heat into September. Our plants have only have grown to 12-15″ in height, although all the literature suggests it can grow to 2′ or more. Darrell suggests that we plant this Gentian in a more fertile soil to attain full height, and I”m ready to find a few more spots in the garden that will accommodate this lovely specimen.The 2″ chalice shaped flowers face upward, catching the morning dew.
Hardiness range is USDA zones 3-8. Darrell shared in the comments box that the parents of this hybrid are of Japanese or Korean ancestry, perhaps G. makinoi, and not from more fussy alpine regions. All the more encouragement you need.