In the wild, Y. whipplei seeds become very dry, then are blown all over. Many are also left on the stalk which eventually falls. They fall under the protection of the drying stalk, then germinate after a rainy season. I suspect that some may even wait a season or so, since I see new seedlings sometimes within a cluster of larger plants that are more than a year old. While Y. filamentosa may not have identical characteristics, I hope this helps. Marguerite