These indigo flowers have root bulbs about the size of quarter. Are they some form of allium or something else? And are they edible?
Here is a link that might be useful:
Grape Hyacinths, Muscari
Grape Hyacinths are actually a part of the lily family; their name results from the fact that they look like hyacinths. From the genus Muscari, these easy to grow bulbs are winter hardy in zones 3-9. One bulb results in a single flower, which reaches about 10 inches in height. For maximum impact, consider planting a large grouping of grape hyacinths. In addition to a pretty landscape, youÃ¢ÂÂll also enjoy the lovely musk-like scent each time you wander past.
There is some question over their toxicity if eaten?
Grape hyacinths, often grown for their fragrant smell, are not toxic. However, it is easy to confuse them with common hyacinths, which are.
Grape Hyacinth contains comisic acid which acts like a saponin, this can be poisonous to some species especially fish. It is poorly absorbed by the human body. Has been used with other species of Muscari, for its diuretic and stimulant properties. Conflicting information in sources list M. armeniacum as poisonous and non-poisonous, we have erred on the safe side and list it as poisonous.
Here is a link that might be useful: Muscari armeniacum
I doubt these are M. armeniacum, as those are quite rare in the States and have numerous flowers on long pedicels. They aren't M. comosum, because those have pedicels rising, instead of nodding. The two remaining, and our most common species are M. botryoides and M. neglectum. M. neglectum has perianth tubes that are oblong and blackish-blue, and 20-40 flowers per raceme. M. botryoides has perianth tubes that are globose, and sky blue. Your plant is likely Muscari botryoides, which is often called the Common Grape Hyacinth.