I've made several bow tuck bags as well as other purses and totes and use cotton all the time. It holds up well through the season(s).
Here's a couple of tips I came up with to help the bag last through more than one season --
- use Scotchgard to help with warding off dirt.
- might consider buying purse feet to keep the bottom of the bag clean
- reinforce any stress areas
-- on the bow tuck specifically, the bows that are tied on the ends need extra reinforcement. my first one popped stitches after several months of re-tieing.
Hope this helps and have fun making this bag - it's so easy and fun to make !!