It seems ease of germination is related to whether the plants grow in the east or the west. As we are slap bang in the middle it's hard to know where we fall. I already know from watching my own garden that annual conditions can be responsible for whether a plant performs or not. Conditions in central Texas are often unpredictable. A wet winter; a dry winter; a cool spring; a warm spring; a dry summer a wet summer etc. We have it all and undoubtedly germination is affected by these conditions.
My Texas Wildflower book says they germinate easily but at least two sources say that the seeds need several weeks of 40° temperatures to initiate germination. Some winters may provide those kinds of temperatures but I decided to take half of the seeds and give them a few weeks in the refrigerator. On advice I wet some paper towel, sprinkled on the seeds and enclosed in a plastic bag. The rest will be sown in the ground with the hope of perfect conditions this year for their germination. Meanwhile I shall be checking the nurseries for 4" pots of this plant. I would like a few more of these beauties in my garden.