How large are they?
Have they been hardened off?
grown from seed: a bit longer, bought in pots: any time.
so long as the ground isn't frozen, or waterlogged, they'll be fine.
I agree with Hostafan1, but do watch out for slugs which just love them (delphiniums that is)!
Bumping this thread to save starting another one!
I have a load of foxgloves in 3 inch pots that I am taking to the charity shop next week as I need the space. I do information sheets for prospective purchasers so they've got some idea of what they are getting
Just wondering whether it's okay to plant them out yet or wait until September time, and keep them in shady spot ?