Leaflet lets you add POIs on a OSM base layer map, you can also extract information from OSM about trees and bushes. If you use dumped data from OSM your data will be considered opendata as well so merging them will mean that you can not prevent other people from using you data.
In short: You do a overpass turbo query to dump data from OSM and import it into sqlite, build a GIS index, serve it as geojson, display that on a slippymap with leafletjs and write an end point to update the data.
