Answer: Thuja orientalis 'Blue Cone' is a named cultivar that is propagated by rooted cuttings, so you would not be able to grow it from seed or purchase seedlings. Since you mentioned growing it as a potted plant, I should mention that you will need to provide it with a winter chilling period each year to keep it healthy. As a container plant it will not tolerate extreme cold (the soil should not freeze), so you would need to store it in a location that is between about 35 and 40 degrees each winter. It should also be outdoors in at least a half a day of direct sun during the growing season. Since it is not winter hardy in your area, you would probably need to try mail order. In no particular order, Forestfarm offers a nice selection of Thuja, although not this particular one.
Wayside Gardens offers some, also.
If you truly want arborvitae seedlings or small transplants, you could try one of the specialty nurseries such as Carino.
Good luck with your project!
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