When people click on a plant they will see who owns the plant and if they are willing to trade or sell.
So you will need to complete your profile page and create a list of plants that you have. For each plant you enter, there will be an option to click on plants you are willing to trade or sell.
Look up on top of the page and find Plants Database; click on that; type in the name of the plant and it will take you to the database for that plant. Sometimes/often it will tell you how many members and which members have the plant, but now always. Another way to tell is to see who has added photos for the plant - that's not always reliable because photos can be taken in places other than the gardener's home garden.
Daylily (Hemerocallis 'Possible Side Effects')
Hope this helps.
Edited to add more info.
