lamb's ear
Stachys byzantina

Hardiness: Zone 4 to 8
Plant type: Herbaceous perennial
Height: 9"- 1.5'
Spread: 1-1.5'
Sun: Full sun 
Water: Dry to medium
Bloom time: May to July
Bloom color: Purple-pink
Soil: Average, very well draining soils.

Notes: Avoid overwatering as wet leaves invite disease, as do high humidity summers.

More information on this plant here.