It's obviously time for us to really focus on how to germinate our seeds. It's easy to find the 'how to' for a lot of seed, but some are both confusing and contradictory. I have seed of several Dracocephalum, including D. grandiflorum, D. heterophyllum, D. stamineum, D. nodulosum, and D. imberbe. Advise PLEASE.
I am something of a Dracocephalum fan too and have grown a small number from seed... in memory, D. ruyschiana years ago; D. foetidum, D. heterophyllum (of interest to you), and D. poulsenii in 2010. For the latter three species, my notes say I got germination in a week or less at room temperature, with no conditioning (that is, no previous stratification, etc.). Of course, you could also set the pots outside and no doubt get equally good or better results.
Dr. Deno only commented on D. renati(i?) and D. tanguticum; both germinated under a variety of conditions.
So, I suspect (but don't know, of course) that no special treatment may be necessary for the genus in general... ??
P.S. Dracocephalum nutans was easy from seed also... probably too big for most rock gardens though.
Dracocephalum botryoides seeds germinated without cold conditioning for me (or perhaps very little.) Planted in a pot outside at the end of April in zone 4, they emerged the end of May.
I planted Dracocephalum ruyschiana Feb 20 in a pot outside. Nothing germinated until the third spring!