PlantFiles: Amethyst Sea Holly
Eryngium 'Sapphire Blue'

Medium 2-3' - Plant 18" apart. zone 5-9. Large steely blue flowers are sterile and long lasting. Even the stems are imbued with color. Deer and drought resistant.

I thought I'd try the Sea Holly as it looked interesting. I am in Iowa and my husband has Rattlesnake Master and I think it adds interest along the same lines.

This is the first summer in Z5 and I am hoping it will winter over well as I really think I have found a neat plant to really add a punch of "True Blue" to an area.

Sea holly 'Sappire Blue' is a beautiful plant whose leaves have light colored veining. The blooms arise from a rosette and turn an interesting shade of blue as the blooms mature (must have enough sun for the blooms to gain the blue tones). The blue coloring extends to the stems as well as tints the foliage which is leathery and bristlely.The blooms start out green in May and keep intensifying in color and each bloom has a star-shaped spikey collar. The stalks and blooms, if left on the plant, even add fall and winter interest. In Zone 9, it usually is an evergreen plant.

This sea holly hybrid has the largest blooms of any sea holly and is a cross between Eryngium bourgatii and Eryngium alpinum which are both native European Sea Hollies. The blooms make excellent fresh-cut flowers for bouquets and are easily dried for long lasting flower arrangements (the bloom stalks must be dried in low light, preferably in a closet so the blue stays a deep shade). It prospers in poor well draining soil. Do not fertilize. If the soil is rich, it will grow taller than it should and the stalks become weak.

Although most sea hollies can become invasive, 'Sapphire Blue" is sterile so there is no need to worry that it will take over your garden. Producing a long taproot, it is difficult to transplant as well as divide, but it makes it a very drought tolerant plant. If the plant needs to be moved, down deeply enough to not harm the tap root. It should be dug in the fall after the foliage has died back to ground level. To propagate, it is best to take root cuttings in the spring and plant them in light well drained soil about 2 inches deep.