Ah, let's give you an answer to your question then :-)
Short answer, it depends, so shoot the fastest shutter speed you can.
Elaboration: A little breeze will move things slowly, and the movements will be small. A gale will move things very fast over a large area (read, entire branches and tree tops moving...). The more wind, the faster shutter speed you are going to need.
Compound this with focal length and subject-to-lens distance (read, magnification). Shorter focal lengths and greater distances will minimize the effect of movement (by everything, not just the wind). Longer focal lengths will do the opposite.
My approach is to optimize shutter speed by a) using camera movements to adjust the plane of focus and allow a larger aperture to be used (I shoot LF), and b) use a faster film (ISO 400 is my outdoor standard).
After that, there are some things you can do to improve your chances when the wind is moving your subject around. a) keep your distance and use a shorter focal length lens (as above), b) be patient and wait for lulls in the wind. Often, even on a quite windy day, there will be short periods where the wind dies down for a second or two. I've waited hours at times, both successfully and unsuccessfully, for the wind to die down enough to get a shot. c) If there are only one or two things moving around in the composition (and assuming you have "recomposed" to eliminate as many moving objects as possible) you can try to catch the movement at the apex, i.e., the point where the direction changes and the moving object is motionless. This can work, but you can also burn a lot of film trying... It depends on how important the shot is to you.
Lastly, you can use the blur; use a slower shutter speed and incorporate the blur, if you can adjust your vision to that. Or, come back another day.
Hope this helps a bit,
Subject movement is commonly discussed in sports photography. You basically need to know how far things will move on the film during the exposure. This is basically given by three things: the speed and direction of your subject, the distance to your subject, and the angular coverage of the lens. If you are close then the movement will be magnified, same goes for narrower angular coverage (longer focal length) magnifying movement. If you are using a wide angle lens from far away then you may be able to get away with a 1/30th shutter without showing much movement but if you are close by to exaggerate a foreground tree then its leaves and branches may move very fast across the film and you may need 1/500 or faster to freeze them. Modern cameras with 1/8000th shutter speed can freeze it with fast enough film on grey days, I know I'm shooting more Delta 3200 rather than 400 these days as it is so grey up here too.
I still ask why must you freeze the motion entirely? I suppose you are wishing that it were NOT a windy day and you are trying to take a picture as if it were not windy. I like to photograph things as they are in which case some motion blur records the facts of the situation.