Blue Thistle Flower Name. Dry shallow or rocky. The genus name Planum translates as flat.
Eryngium alpinum blue alpine thistle. Its actually a herbaceous perennial weed and a parsley family member. Plumbago grows best in zones 8-11 in very fertile well-drained soil.
Eryngium bourgatii Gouan the Pyrenees blue thistle.
It thrives in partial or dappled shade and prefers moist soil and the limited sites where it grows in Scotland are at the edge. These prickles are an adaptation that protects the plant from being eaten by herbivores. The genus name Eryngium is Greek. Echinops ritro the most common blue thistle.