Germinating Cowslip Seed, Rosea Lavender Culture

I would like some advice about rosea lavender – I am reading that it is not too hardy and can get root rot. I was planning to grow a little border of it above a herb garden. We are zone 8/9 and the site is well drained.
Another question – my husband is having trouble germinating your cowslip seeds – any suggestions there?

Rosea lavender is hardy in zones 5 to 8 and might have a bit of trouble surviving your summer heat. Grow it in high shade and mulch heavily to prevent root parching. Make sure it gets enough water and don't place it in a spot where there is no air movement. Morning sun is probably the only sun it should get. Make sure the plant has excellent drainage and that the pH is slightly alkaline – all to reduce all other stresses.
Sometimes seeds can be prompted to germinate with a cool-warm sequence. Often this is true with wild plants that have not been altered much by human selective breeding such as the wild form of cowslip (Primula vulgaris) we sell. Plant cowslip seed pressed into the surface of a flat of Pro-Mix (a peat moss and perlite based mix) moistened with boiling water and allowed to cool before planting the seed. Cover with clean plastic and keep at 20 degrees Celsius for six weeks, then place in the fridge kept at around 4 degrees Celsius for a further 6 weeks then raise the temperature slowly to 10 degrees Celsius and keep it there for 6 weeks. If there is no germination, repeat the cycle. If after all this treatment you still do not have success, contact our customer service department (custserv@richters.com) for help.