Nook+ has a new section for Plants! If you look at the navigation bar at the top of the page, you should find a new Plants button between Artwork and Settings. (You may need to refresh the page to be able to see it.)
Plants are shown with images, names, links, prices, and sources.
As in the other sections, you can search the displayed plants by name.
You can also select a quantity of them that you have for a recipe, and filter by which ones you have and which you don't. If you have the Sync feature enabled, these quantity values will be synchronized along with the rest of your data.
Please let me know if you experience any issues or have any suggestions to improve Nook+ further.
Enjoy!