Never heard of chamomile as being "invasive." When I was a kid growing up in Maine it grew wild in our driveway. We called it pineapple weed since it smelled like pineapples. I think you can buy a wide variety of chamomile seeds from suppliers in the US. I plant roman chamomile in a pot here in central Florida.

Zorba, there is a "pineapple chamomile" which is indeed considered a weed. The plant (Matricaria maritima) is often mistaken for chamomile (Matricaria recutita) and is in fact, closely related. Chamomile, the herb, is quite rare east of the Rocky mountains where pineapple weed is quite common. Pineapple chamomile is native to North America and it also makes a tasty tea. Some prefer it to the common chamomile.

"Distribution & Habitat: Pineapple weed is found in almost all waste areas. It can be seen growing in cracks in the sidewalk in the centre of most towns and along many a backwood s dirt road."

I have German chamomile that volunteers in my garden. I pull it when it grows where I don't want it but I wouldn't call it invasive.

Greenhrs, German chamomile is native to Europe. If you post a message on the European forum here at gardenweb I think someone there will be able to lead you to a source.

Good luck