8 September 2026

Last week I was happy to see one of my favorite September flowers blooming at Sewickley Heights Park: Bottle gentian (Gentiana andrewsii) a perennial native.

The plant was a little worse for wear but for the most part it was still tightly closed and waiting to be pollinated. Will the tiny bug on the leftmost flower do the trick? No.

Bottle gentian flowers — superzoom (photo by Kate St. John)

For pollination it takes a bumblebee who’s willing to put forth considerable effort.

When the bumblebee has finished the result is a nice crop of seeds.

Seeds of bottle gentian (photo by Kate St. John)

Bottle gentians are so bumblebee-dependent that they are affected by bumblebee decline.

p.s. They are also subject to nectar robbing! The eastern carpenter bee (Xylocopa virginica) bypasses bottle gentian petals by drilling a narrow slit at the base of the flower to “steal” the nectar. Thus the flower is never pollinated. The slit allows other bee species to nectar rob as well.