All my Smartwool socks go in the gentle cycle washing machine (lukewarm) with Woolite, then into the dryer on LOW. They hold up great, but they all shrink just a little and then stop shrinking.....which is why I tend to buy my wool socks a little on the large side 'cause I know they do shrink just a bit.
With wool in general- NEVER hot wash, NEVER hot dryer. Always gentle everything. Then again, you don't have to wash 100% wool as often as other kinds of clothing items. Wool repels dirt and takes a long time to get stinky.