i have 5 different species with at least 6 different varieties in each. totaling around 25-30 different types.... approximately 200 seedlings so far. my question is concerning these guys cross pollinating once transplanted outside. ive read several books on horticulture and plant biology...all say chances of crossing are quite high. my partner seems to think that it is of little concern and plants that could cross can be planted as close as 5 feet with no worries of crossing. i disagree. i know that wind and insects can facilitate cross pollination, wind can be controlled somewhat with barriers etc. but what about a bee or humming bird that can hit thousands of plants a day and cover miles? anyone who is a professional grower or has a degree in horticulture, could you help clear this up? thanks for any feedback!