Etienne,
Just skimming through here. As a note, the database is a great resource and can be used along with the catalogs. If you choose to leverage them to your needs that may and can be possible. I however like to use them as a general lookup volume. If I need more embedded data, I add a custom plant record format (or two, or three) depending on my needs. These are often regional data. As for publishing books. While we all love Vectorworks, it is not a book publisher. I have always utilized other tools such as Pages, Word or Indesign for this. This process allows me to design a master sheet layout and populate as many high res pictures and custom information in the format and layout style I choose. I then have one big master book with a plant per page with seasonal pictures, leaf and flower pictures, bark images, along with species data, and care instructions. All while having a creative layout and my logo and contact info. I would then select the plant types from the master and copy them into the client document that is titled for their job. I used the same for furnishings and lighting and well... everything. We had a spiral binder so these were a fantastic addition to provide. As for images in Vectorworks. I created unique symbols for these botanicals allowing for a more creative way to produce plant imagery within Vectorworks. This takes the gridded confines of a database away, giving me creative presentations.
Hope this helps a bit, feel free to reach out to me if you have any further questions. I am always happy to help find a solution that works best for you specific situation or need while creating rapid and profitable workflows.
Quick sample attached.