The woman at the flower shop inside the grocery store, showed me by pressing down on the petals of a partially opened tulip, that you can force the flower open without damaging it.
This was lit with an SB600 in a softbox on either side of the flower. The strobes were set to manual, and I adjusted the output until I got a result that I like. They were triggered by the pop up flash on my D90 in commander mode. Because I used an aperture of F22, a shutter speed of 1/180 second and an ISO of 200, no ambient light was recorded and the background went black.
Other plants and flowers that I've photographed using strobes can be seen in my strobe lit plant set. In the description, I list resources that I've used to learn how to do this. www.flickr.com/photos/9422878@N08/sets/72157628079460544/...