Originally Posted by pareto 
This is a very common conception. But it is wrong. Wide angle lenses only have a larger DOF if your distance to the subject stays the same, thus filling only a smaller part of the picture. If you get closer to the subject in order to fill the same amount of the picture as with the tele, the DOF is constant.
Here is a good explanation.
That's sort of rephrasing what I said.... you need to be close to maintain a shallow DOF like you'd get with a telephoto. (unspoken: to fill the frame the same way)