focus - How can I achieve this effect, where the flower is sharp and everything else is blurry?

I was wondering how it is possible to take a picture like this.

Please have a look here for some example pictures. The flower is sharp, and everything else looks like taken with a long shutter.

Is that even possible, or do you think it's Photoshop-edited?

I asked the photographer about the lens, and it's a Minolta RF Rokkor 250mm f5.6.

Answer

Looks like it's been shot with a wide aperture (low f number, like f/2.8), from a close distance, with a camera that has a large sensor -- the combined effect is a shallow depth of field, as demonstrated there.

To reproduce, put your camera in aperture priority mode (Av on a lot of cameras) and choose a wide aperture (head for f/2.8 rather than f/22) and get shooting.