I'm by no means an expert and have never succeeded in germinating an allium from seed, but Allium purpurea 'Purple Sensation' has reseeded in my garden. The little leaves do disappear in the summer but reappear the next spring. I would sink your container in the ground for the winter so that you could keep track of it next year.

I love 'Christophii' - the heads are huge! :)

The same happened to me with unusual allium seed sprouts and another bulb forming seed. The foliage disappeared. So I dumped out the pot and found tiny bulbils. Planted the allium bulbils (rock garden) and repotted the other as it has to come in over the winter.
I'd recommend you have a look but repot if you find bulbils. Keep the pot outside in a protected spot that receives lots of snow cover over the winter.

Thanks so much. I was hoping to hear something like that. If I get brave I might have a look at one of my little pots. I still have allium aflatunense in the fridge downstairs.It has been there since last April and hasn't done anything yet but it is supposed to germinate in the cold so I guess I will leave it there.
Thanks again for the help. I love alliums and couldn't resist the spring sale at Gardens North. I have never grown any and 2 bulbs I bought at a show in the winter rotted. Hope I get some green shoots next spring!!
Debbie