Greenberry as a given name seems to have been in honour of one Colonel Nicholas Greenberry (1627-1697), Indian fighter, politician and Governor of the State of Maryland. Early 17th century. Greenberry was a early settler in that state, having come over from England.
To quote from a message board on RootsWeb.com.
"His children (including three daughters) and grandchildren married with many of the other notable familes of early Maryland and the given name Greenberry continues to this day amongst their descendants. GREENBERRY as a surname became extinct upon the death of his son Charles (who had no issue). But there seem to have been many others in the ensuing years who were named in his honor though not directly related."
Hope this is of help, Margaret.