I recall posting earlier in the year about this plant. Here's a link to the thread.
[Note: mine is still under a foot tall.]
~Rosemarie

Here is a link that might be useful: Mar 03 thread on this

They seem to really vary in height, and tags are often not correct on the variety in the store.

Mine are in a perfect spot, rich compost, regular watering. The first year they barely grew more than 3" taller and bit more in width. Then they got leaned on by my CA poppies (I sowed too many!) and stopped growing entirely. They did survive though, and last week I noticed that one of them had shot a single branch (with leaves) 2' in the air!

Woohoo! Who knows when it will decide to do anything else?? Like polemonium, this plant seems pretty touchy. Mine have flowered profusely, but not done much else. We'll see how the second year goes, and how tall they end up. Mine are right in the front of the border so they won't be allowed to get too tall!

I have read that these are slow growing but that they can be urged on with regular fertilizing.