They won't bloom all summer but if you cut them back when they finish you may get new shoots that will bloom in the fall.

Mine will bloom all summer (that's one of the very few benefits to a cold climate) but the blooming stalks get shorter and shorter with fewer and fewer flowers until they aren't really useful. I plan to try the cut-back-to-the-ground system this year on some of them, but I'm afraid they won't have time to get blooms up there again, considering that they are in the middle of their first bloom only now - and these are established, 2-year-old plants. With your warm days and cold nights, instead of cold days and AND nights like mine, yours might do well that way. My just-started-this-year plants are only just developing blooming-stalks-to-be and teeny-tiny buds. On the pro side, they don't mind freezing at all, so they should go farther into the fall than most other plants.

Jeanne

Jeanne, my delphs are just about where yours are. WOnder if it is more day length that affects them? Mine don't bloom all summer though. I am just cutting down the first to bloom now.
I want lots more differetn colors! I seem to only have 3 shades of bllue and one is an earlier type. I Planted many differnt kinds this spring but by the time they survive to be planted and then survive the delicious leaf stage in slugdom I don't get many. I do have one survivor of my New Zealand hyb package of "Short" delphies though. IT is a purple with a dark bee, not my favorite combination. It should serve to spark up one of my flowerbeds though where there are too many pastels.

We grow belladonnas, magic fountains and Conn. Yankees. They are just starting to bloom now, maybe a bit later than usual because of our drought - no rain in June. I cut them at ground level or slightly below. That's finicky, but seems to encourage new, tall bloom stalks. Ours typically bloom thru early and mid summer. They take off in Aug. and usually come back when it cools down. We grow ours in tomato cages mulched with wood chips. I'd love to hear how others grow and cut them.