10 Flowers in an hour is about what you should be able to get. I only spot 5 because I tend to click through the site quickly. They seem to not be pickable any time sooner than 5 minutes or so.

"Oops this isn't yours" happens when you have more than one window open and they are both in the same subeta URL (.ws or .net). If you click on a window that is on the same URL but has no flower.

It also happens if you only spot the flower after pressing the back button.