Years ago at another garden they self-sowed prolifically in pots near where they had flowered, but I can't seem to make that happen indoors. I soaked the seeds 48 hours in 9:1peroxide water with a drop of Superthrive, then did the paper towel/baggy trick 1 week warm, 2 weeks cold in the frig. Then on 3/11 I took them out of the frig and planted them in a 3" pot in seed starting mix, more peroxide water, more Superthrive, and put the pot in the biodome over a heat mat. Nothing.
What temperature is your heat mat set on? Most references say to germinate around 65-70 degrees. I would give them another 2 weeks to see if they will germinate and then if none, put them back into the fridge for another 4 weeks. It is possible they will germ in the fridge, checking them once a week should be often enough. Trying to shorten the stratification will work for some species, but for others I never get germ.
They germ so easily/readily outdoors because of the longer stratification period and the varying temps/moisture outside. If I have bad luck with something I'm trying to stratify indoors, I will usually also winter sow some so that I have a backup. I will also double sow (indoors and outdoors) if I am trying some new plants and have no experience with germinating them.