This is Euphorbia cyparissias. It can be invasive so keep a close watch on it's intentions!

Sorry, Volunteer, it's not - if its a Euphorbia at all, its E. pithyusa, good in a rock garden, stays reasonably small.

Sorry, Bamboo, but it's not E. pithyusa. I have this plant too and was hoping to find out for definite what it is. I'm absolutely sure it's not E. pithyusa, and I'm not completely sure that it's Euphorbia cyparissias either. Mine is only about 4 " tall and not succulent. The flowers are absolutely typical Euphorbia though. How tall is your plant Scottypippin?

With you on this one Beatie, it is invasive but easy to pull up and I love it.

The trouble with Euphorbia (I don't say above it definitely is pithyusa) is that there are many subspecies - if you get up a gallery of pics of E. pithyusa, there are 5 or 6 different forms because some of them will be sub species - and one of the ones I found looked exactly like this, unfortunately without any other name. Let's hope somebody gives it a definitive identity...

It is a Euphorbia and is beautiful in the spring with lime green bracts, it spreads well and I love it. Judy you are right it is very easy to pull up where it is not wanted, worth keeping though.