So, the last three flowers I have gone to pick in a row, I've gotten this message,

I figured it was possibly because I found them relatively soon between one another? It was about 5-10mins in between each, but I'm just getting irritated that I'm not able to pick any of them. xD

I got that message too.... I didn't know what to do, so all I did was logout and log back in and got the flower

i got the message too a few times :(

If you have tabs or multiple windows open, you have to make sure to grab the flower from the most recently opened window/tab. For timing, I've found that flowers show up between 5-15 minute intervals.

At the time this happened, I only had one tab open.