While it is true that there are sterile varieties of butterfly bushes, those varieties are only roughly 98% sterile. This means that there is still the possibility of producing viable seed. Those mostly sterile varieties have the possibility of cross-pollinating with the invasive non-sterile varieties that are already growing throughout the country and forming resilient virile varieties. It has happened before with other “sterile” varieties of invasive ornamentals.
Hi Mary,
While it is true that there are sterile varieties of butterfly bushes, those varieties are only roughly 98% sterile. This means that there is still the possibility of producing viable seed. Those mostly sterile varieties have the possibility of cross-pollinating with the invasive non-sterile varieties that are already growing throughout the country and forming resilient virile varieties. It has happened before with other “sterile” varieties of invasive ornamentals.