If it is not an incorrectly entered plant but an incorrectly uploaded image of a plant you can ask to delete the image or have it moved it to the correct cultivar if you know what that is.
First click the image, this will enlarge it. Scroll to the bottom and you will see a box for "Actions". In the box will be several choices, click "Move this image to another plant" if you know what plant it is.
Or "Propose this image be deleted" if you don't know the plant in the image.
Whichever link you choose just follow the instructions to move or delete the image.