Well Will thinks you used AF, I don't know. I never would. doesn't help with macros.
My hint is that is the ONE thing you want to do manual. Just use your eyes. Takes far too much time to start selecting points and all that and then do you like it. Your DOF button will tell you what the picture will really look like.
As to the speed being too slow, Will is right. 1/400 in the wind
Tell the guy who told you about 100 ASA to go and shoot some birds. Or flutterbys
The DOF is too shallow.. if you do this to get a special soft effect like Mandy D or in here
get at least one flower center really very sharp.
I now I'm again lecturing here. If I annoy you, I'll stop. And the colours are gorgeous, so is the composition.