I agree with @psweet that erasing parts of the image does not really help, I would recommend sticking with a simple square/rectangular crop rather than the more complex shape crop. An initial image with the target plant at image center is ideal. If the plant is well centered, no cropping need be done. As @erininmd noted, a closeup is a good opening shot. If a photo of the environment is included, be sure the plant is in the photo. If the photo is of the broader habitat without the plant, then that should not be included in the set of observation photos as this will have a negative impact on the training of the computer vision for that plant. This splitting out of the habitat photo can be seen on the observation at:
https://www.inaturalist.org/observations/25368804
For a discussion on showing habitat, see: https://forum.inaturalist.org/t/suggestion-on-how-to-include-habitat-images/3553