Violas and 'Black Scallop' Ajuga reptans in Containers

When I was asked to do a few container pots for an April 15 event, two of which would remain on site, I struggled a little to envision anything except pansies that would survive a potential April frost.

One rule for container planters goes like this--a thriller, a filler and a spiller. The container above had a yellow ranuncula for the thriller.  The thrill is now long gone with two seed pod still sticking out of the center. The violas and a couple of pansies (because we ran out of violas) fill out the bulk of the container and are still doing well today. The surprise was the Ajuga reptans 'Black Scallop' which has gone bonkers. It is a ground cover perennial that had blue flowers in April but after blooming sends out runners in every direction in a little spring fling as one Rainy Side Gardener at Rainyside.com describes it.

Behind the rock are some Big Leaf Ligularia, Desdemona and Othello but I can't tell them apart!

The thrillers for the containers that remained on site after the event were white bleeding hearts, which are also still in bloom; the violas and the ajuga were both fillers but today have become increasingly good spillers:

Note:
I bought a whole flat of 'Black Scallop' ajuga the following year and it was not the same. Could this ajuga have been mislabeled and really be 'Catlin's Giant'?? In 2016 I bought six of those, and they are big and behaving more like the ajuga in this pot...