For droughtprone zones and areas where you need a touch of colour, consider a liberal planting of this unusual perennial flower. Greyblue, leafy stems are tall and straight, keeping the thistlelike flower heads upright and visible to passing butterflies and bees. Best in full sun, the 2–3" blooms give off a wonderful blue hue, which is quite breathtaking in groups or mass plantings.Eryngium alpinum