Larkspur bud rot

 These are my seedings that were sown in February this year. It was my first time sowing flower seeds to fill a corner in my garden that i'm hoping to keep wildlife friendly with acottage garden feel.  Although it faces south west it is shaded by nearby fruit trees. i planted cornflower blue, salvia and larkspur as small plugs direct into the prepared soil, no fertiliser has been used, the soil remains fairly damp in that areacand i have watered on occassions that the rest ofvthe garden needed it. I noticed today that just under half of the forming budsvhad turned black and mushy - i'm supposing this is rot.

is there anything i should do now to try and salvage the plants? will they send out new buds? could i try growing these again next year or could you recommend a different but similar cottage garden type plant for these conditions to try next year? Thanks in advance