Someone said that this is probably an invasive species that the Chinese government wants some schmuck to plant and cause an ecological disaster. But I don't see how it wouldn't be absolutely trivial for one of their spies to do it without such an absurd scheme. They are literally being exposed by the people who got the seeds, those seeds can be sent in to the authorities to be identified and if they are invasive an investigation can be made to identify exactly where they came from. When they could just have put them into a bag of rice that their agent orders form china, if it were magically found it would be called an inadvertent contaminant, and they could go out anywhere and just drop it in a field.