TIP: Garlic Mustard was introduced to North America more than a century ago as a tasty, garlic-flavored herb. It often occurs amid spring morel patches and features small, white flowers with four rounded petals. Garlic mustard is now a dangerously invasive plant considered a major threat to Illinois forest plant communities. It’s easily spread by hikers accidentally transporting seeds on shoes. Collect this garlic herb with extreme care.