Given you know it's name do you want to change it? To change it:
Go to profile. Scroll to plant. Don't tap on it. Swipe record from right to left = brings up edit button. Select encyclopedia link. Tap and select "change plant link".
You should be able to just tap on link above this photo which says 'Help Mo...' You'll then have an option to either search database for this variety or tap on lower link which says 'contribute to the database' where you then just manually add the details yourself....
No worries. If you wanted to change a plant name for one that's already named, you'd go to your profile and scroll to plant, swipe right to left and tap red edit. You then could tap on the green encyclopaedia bar at top of page and then a change plant name would appear. Hope this helps 👍