The flowering alliums are apparently started just like edible alliums. No need to refrigerate. They are biennials so it takes a second year to flower.

Here is a link that might be useful: How to grow alliums from seed

Most flowering alliums are frown from bulbs but it is possible to grow them from seed.

Hybrids will not come true from seed of course. Sow ripe seeds as soon as possible or store in a fridge and sow in spring or indoors. Without cold storage the shelf life of the seeds is very short. Most will germinate within 12 weeks. It will take several years for plants grown from seed to reach the flowering size.

There are many 'how-to' discussions on the Allium forum that the search will pull up as well as into on the Bulbs forum and the Perennials forum.

Dave

Thank you gentlemen.

Allium flowers and seed pod are very much like onion(Round globe formation). I thought that it should not require refrigeration fo dormancy purpose.

I will try to germinate some right away and will refrigerate the rest for spring.