Spanish bluebells, Hyacinthoides hispanica, are considered invasive in the Pacific Northwest. They spread by seed and root runners from their bulbs and are very difficult to get rid of. I know because I have an ongoing battle in my yard with them.

There is no easy way to get rid of them. Research says that the best way to control them is by digging them out. Digging them out is difficult because their numerous bulbs that can be very deep in the soil, more than 12 inches. Besides removing the bulbs, as much of the runners as possible should be removed also. It is easiest to remove them after the leaves appear and the soil is moist. Use a garden fork as close to each bundle of leaves as possible and loosen the soil. Gently pull the plant and remove the bulbs out of the soil.

As you mentioned, Spanish bluebells can be in and around tree and other plant roots. In this case when the leaves appear, cut them off every couple of weeks. Over a period of time, which can take up to a year or two, the plant will starve. Without light, carbohydrates cannot be made and the energy reserves will be depleted and the plant will die. Never allow this plant to go to seed which will only further the spread of Spanish bluebells.

All parts of the Spanish bluebell plant are poisonous. When working to remove them, be sure to wear gloves and place all parts of plants in a black plastic bag and dispose of them in the trash. Do not add any part of a Spanish bluebell plant to a compost pile. This will only add to your problem as they will most likely reappear again.

There are no herbicides that will touch bluebells. They are persistent and you must be too in your quest to get rid of them.