I have also been visited by plants in my dreams.  At the time it felt significant.  Now, I do not think so.  It seemed like the plants, in my case Syrian Rue, Mimosa Hostilis, and Ayahuasca, were using my dream state to send me messages, but after awhile I realized it was always the same message - not the messages you get while tripping, but the messages you get from any old dream character.  Nothing more than what I already had going on in my head, only presented to me in the form of a play.  The plants were trying to get me to consume them. 

I did feel nice having been spoken to by these sentient plants who usually require a much more difficult experience (tripping) to get through, and in retrospect I feel sometimes when we get nice tingley warm feelings as a result of a dream scenario we like to adorn that feeling with significance but really the source of the significance is a desire for everything to make sense.  Unfortunately, everything does not make sense, and dreams are just what happens when you are asleep, which by definition means your information is coming from you.

In the school of thought pertaining to dream analysis, the most likely solution is that you are thinking about the plants, then you go to sleep, and... "In mother Russia, plants think about you!"