More sources for the U.S. are listed at the Facebook group called Snowdrops in American Gardens. Look under the Files section for a document called Galanthus sources. It is usually up to date. The only UK source that will ship to the U.S. is called Morlas Plants.
https://www.morlasplants.co.uk...
They sell dormant bulbs. They take orders from January through the end of March and then they ship bulbs usually late summer or early Fall (August/September). Shipping is expensive due to the extra paperwork, but it's the only source open to Americans in the U.K.
Mrs. Macnamara covered in snow. These bulbs came from Morlas.
Steve