Did you take the seeds off the flowers? They will germinate and be ready to plant out in about two years so you have to be patient.

My dwarf delphiniums have started to turn, I just tidy up any fallen leaves and leave to die back completely. Mine are in pots as I have found the slugs have rather an appetite for delphiniums. When they have died right back I move them to a frost free area and leave to be brought out again when all danger of frost has past.

It sounds as if the larger one has been overwatered. If it feels too wet let it dry out a little. It should return next year if it hasn't rotted at the root.

If they are in the garden, try mulching with straw or gardeners fleece during very cold snaps and keep a look out for slugs and snails.

To be truthful I have always found delphiniums in the garden very difficult to keep over the winter, but I think that is due to the wet cold northern climate in Yorkshire.

The one you describe as looking a bit black on the leaves may have Delphinium Black Blotch - if it is that, remove the plant immediately, dispose of either by burning or at least not composting it, nor in the garden recycling, and don't try to grow another delphinium in the same spot.

Delphinium Black Blotch is new to me Bamboo, will make a note of it just in case. Thanks for the info & advise.

I didn't know about it either, Grannyb, but someone posted a photo on another website of 2 completely black, even black flowers, delphiniums - so I had to do a bit of research. Sometimes I think ignorance is bliss...

You could be right Bamboo, a little knowledge is a dangerous thing.

A lot isn't dangerous - but not knowing at all means you don't worry!