Hi Jon, What makes you think it flowers in late fall? For the past 5 years or so N. montevidense and similar species have flowered in mid-spring here. I can't help with your question about seed treatment; although it flowers profusely it has never set seed here. Do you know the origin of the seeds you got - collected or from a cultivated plant? Best, John John T Lonsdale PhD 407 Edgewood Drive, Exton, Pennsylvania 19341, USA Home: 610 594 9232 Cell: 484 678 9856 Fax: 801 327 1266 Visit "Edgewood" - The Lonsdale Garden at http://www.edgewoodgardens.net/ USDA Zone 6b