Chamomile Lawn in Saskatchewan

What is the most appropriate type of Chamomile to be used as extensive ground cover or lawn? When and how is the best time to seed it given the climate here in Saskatchewan?

Unfortunately chamomile is not hardy in your province. The chamomile used for lawns is roman chamomile (Chamemaelum nobile) or its non-flowering form, 'Treneague'. Neither is reliable as a ground cover in zones 5 or less. Even zone 6 is marginal, and only zone 7 or higher is really reliable enough.