About a year ago, I was going into a restaurant in Santa Clara when I spotted an interesting flower box combination. Amid the yellow and orange marigolds were rigid, spiky thistle like things that were blue. Now it wasn't just the flower heads that were blue, but some of the surrounding bracts and even the leaf stalks and some leaves. Wow, I was intrigued.
I started doing some research and found out what I had seen was Sea Holly or Eryngium. I found a catalog offering them and ordered Eryngium 'Big Blue'. I got two and planted them in a 5 gallon pot. I got 2 for my mom and she put them in the ground where they were immediately nibbled by deer, despite being labelled deer proof. Later my mom's plants recovered, though mine bloomed first in June. Definitely blue tinged, although not as bright as what I had seen at the restaurant. We picked some stalks while still blue and they dried with the blue coloration intact so I should have some interesting dried flower arrangements. If you don't pick them and let them go to seed the flowers and stalks bleach out to a straw color.
Water needs vary by species but 'Big Blue' is very drought tolerant. They like full sun and well-drained soil.. 'Big Blue' gets 28-30 inches tall and 15-18 inches wide. It's suggested for USDA zones 4-9. Sunset says they attract bees, but to watch out for snails.
Note my mom lives in a deer prone area in Novato. Although they nibbled hers when the plants were small, after they had grown a bit and developed their spines, the deer left them alone.
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