If we read into this poem the supposed "facts" about Miss Dickinson's frustrations in love, we could logically say that she shunned the physical contact associated with intimacy. After all, what is the condition of the flowers who are influenced by the ghostly visitor in marl. They are not as they had been. They are dead. (I had some difficulty with that "marl." The OED gives us something to the effect that it is a kind of soil consisting principally of clay mixed with mixed with carbonate of lime. OK, I'll transpose the defintion into the gray color that she needed for her purposes.)