Coneflowers prefer full sun and lean, dry soil. Usually the stems are very sturdy but there could be many factors causing yours to bend. Are there borers living in the stems? Did you over-fertilize which causes rapid weak growth? Did they get too much water? Is the soil heavy and wet? Try moving them to a sunny spot with sandy soil and see if that helps.
Coneflowers prefer full sun and lean, dry soil. Usually the stems are very sturdy but there could be many factors causing yours to bend. Are there borers living in the stems? Did you over-fertilize which causes rapid weak growth? Did they get too much water? Is the soil heavy and wet? Try moving them to a sunny spot with sandy soil and see if that helps.