The import of any living plant material (including seed) to the US is strictly regulated by US authorities.
In order to import plant and flower seeds to the US, please download the instructions for the application of a free-of-charge "Small Lots of Seed Permit"
by APHIS (U.S. Animal and Plant Health Inspection Service) as PDF-file
* (5 pages, 530 kB).
* Adobe Acrobat Reader
for viewing PDF files is available for free
in English here.