Q.Outer Sheath Of Stem Being Destroyed On My Lobelia Queen Victoria.
Bought two queen Victoria lobelias, and left them outside, next day the outer sheath of stem on one had been lost. I brought them indoors, the other plant is also losing the outer red sheath. Both plants have grown at least six to 10 inches since purchase.

Certified GKH Gardening Expert
They can be a bit sensitive to change or drying winds. Some lobelia can be a little sensitive to afternoon full sun, as well. The only thing to be done from here is to give it proper care. That will nurse it back to health.
This article will offer more information on the care of your plant:
https://www.gardeningknowhow.com/ornamental/flowers/lobelia/growing-lobelia-in-containers.htm



