>Hi Jim: > For all these plants. heat. Dear Alberto; DUH! I stupidly admit you are surely correct. Here in my cold climate I keep it from freezing, but they it has been outside down through temperatures as low as the high 30s F . Only when it is freezing do I bring it in to my 70 F room temperature. OK. It stays in now until...... I have grown N. longifolia and whatever the common 'walking iris' is these days N. gracilis or N. northiana and under similar care they bloom reliably. This may just be a little more in need of warmth. By the way this species is also google-able as N. coerulea. And.... the cv 'Regina' seems to be 'the' form available in commerce in the US. Anyone know the origin of this cv? Thanks again. Jim W. -- Dr. James W. Waddick 8871 NW Brostrom Rd. Kansas City Missouri 64152-2711 USA Ph. 816-746-1949 Zone 5 Record low -23F Summer 100F +