I have the words from the extra letters plus the 3 letter acronym but, alas, what I know about flowers is next to nothing so I've been fruitlessly staring at the grid for about 2 hours now.
So far I've spotted a a time of day in the afternoon that is also the name of a plant called Mir..... Jal..., unfortunately there is no J in my grid so that's another dead-end.
There's also a 4 letter country in the SW corner related to a particular bear who, I believe, is fond of "snack time" so I might try that angle for a while - a very short while.
Then I'll grab some much needed Zzzzz and see if tomorrow brings some inspiration:-)