We fight the garlic mustard every spring. We have one small wooded area where we've actually been fairly successful. Garlic mustard is a biennial, so it grows a rosette of leaves the first year, then blooms and spread a bazillion seeds the next. This time of year is when last years plants start blooming, so I trolled the small wooded area for plants --I found and pulled about ten, which is really good --it means I only missed ten of the hundreds of first-year seedlings last year. In a few weeks I'll have to look for areas that are carpeted with seedlings --just one plant that you miss, or that blows into your yard, can leave 500 seeds that remain viable for five years.
In addition to the garlic mustard, however, I also found my favorite daffodils blooming. I wish I could remember what they're called, so I could plant more :-)