Sue, good suggestion! Now that you mention it, the categories might be just as good as the tagging idea...I think it comes down to 'is it just as easy to create a list out of the categories as it would be to tag them from the get-go when I add them to my wish list?'
There is also a 'comments' section in the plant management list, too, where comments could be put in...
So, I guess what this means is that I should have asked that these features should be available upon adding a plant to the list (not as something you have to go back into your list to do). It's just that one extra step that, when done hundreds of times, adds up to a lot of 'wasted' time.
Thank you for pointing out my 'error'!