My inspiration Pinterest board:
https://www.pinterest.de/aleksdoesart/botanial-illustration/

A bunch of pictures I took in the local botanic garden – these are not all of them, for the rest, I still need to look up the names of the flowers:
https://www.pinterest.de/aleksdoesart/botanischer-garten/

My realistic line drawing – I intentionally left some parts less detailed then others, the less detailed parts will only have a very light wash of watercolor or stay mostly blank:
 


I added watercolor to turn it into my stylish illustration:

And another one:

 This time, I did thinner and more sketchy outlines: