Do you have any pictures of the plants and/or of the flowers?

I have a few kinds of monkshood and most are in bloom or just finished blooming. The ones in shadier areas bloom a little later than the ones in the sun. Some monkshood are sturdy and never flop over yet other monkshood in my yard are kind of wavy, taller and flop all over the place. My sturdy one I do not have a name for (just monkshood) and it has dark thick finely cut leaves whereas the 4-5' one (Spark's Variety) has light wide leaves and definitely not a nice tight flower stalk. Its flowers are spaced further apart on this wavy long flowing stem. Both of these have the purple flowers. There is an article on the Spark's Variety at...

http://www.paghat.com/monkshoodsparks.html

Maybe you have Acontinum x. arendsii aka A. carmichaelii 'Arendsii'. It is a very sturdy monkshood and there is an excellent article about it on...

http://www.paghat.com/monksarendsii.html

Check out their website. They have a lot of varieties and maybe in there you will find the kind you have and why it blooms later.

Monkshood is very very poisonous. Never touch it with bare hands in case you accidently touch your mouth with your hands later. But I love the flowers and the form of the plant and enjoy having a few different kinds of monkshood here in the flowerbeds.

Brenda

Must be A. carmichaelii, strong stemmed, glossy forest green leathery foliage, flower heads produce in the Fall and very hardy to our zone.

Sharon