Alpine Hyacinths (Brimeura amethystina) is another true blue that is often unknown to many gardeners. It is a spring flowering bulb. It blooms mid May here. It is diminutive, but at the edge of a walk like in my garden, it is quite pretty. It will reseed if conditions are right. I have more than the few I planted years ago, and I happily saw a new one blooming across the walk this spring.