Part of the design of our database was specifically designed to address this kind of thing. We have what we call "Parent plant entries". Take a look at the parent page for irises:
Irises (Iris)
As you can see, there are places to put whatever kind of text you want. For Rhipsalis and others, we can make a parent page for them, set a moderator for that kind of plant, and then that moderator can put all the text in.
As near as I can tell, this parent plant feature provides exactly the central place that you're describing. If you'd like one setup for this plant, and if you'd like to moderate it, I'll set it up for you.
