It is true that daffodils are one of the best surviving bulbs around, but it can be killed.
Here are some of the ways:
- If you pull the plant and forget about the bulbs, they will dry out. Once dried, you can't get them back.
- If the bulbs are allowed to stand in water-logged soil, they will rot and disappear.
- Dow Chemicals has a Tordon Brushkiller with penetrant that is supposed to work.
- Don't use a broadleaf herbicide - daffodils are narrow leaf and thrive on getting rid of the competing broadleaf "weeds".
- The herbicide "Roundup" does work on daffodils once they emerge. If the bloom is gone and the leaves have yellowed, Roundup will not work. It needs actively growing vegetation.
