You can use every part of the plant, leaves bulbs and flowers, great addition to soups, salads, eggs or potatoes.  Add at the end of cooking otherwise flavour is destroyed. 
Hardiness: Hardy
Height: 30 
Spread: 15cm 
Soil type: Moist, well drained 
Aspect: Full sun or partial shade 
Flower colour: Purple 
Flowering time: Summer