Bupleurum seeds

I would like to grow some bupleurum rotundifolium from seed. I am planning to sow in seed trays rather than sowing direct but have had conflicting advice as to whether they need light to germinate or cool dark conditions. Can anyone help?

Thanks

Sow on the surface and then sieve a very thin layer of compost over the seeds.
http://www.norfolkcottagegarden.co.uk/shop/item/Bupleurum-rotundifolium

It can self seed, so can't be too fussy

I tried this once.

Can't remember what I did.

It didn't work.

I tried this once too (2 years ago) and not one seed germinated. I put them in the freezer for a week before sowing which was recommended to me - not sure if that was bad advice or I just failed  I will be very interested in how you get on so good luck