It was touch and go for the first couple weeks when they appeared to be dying but shortly after that they started perking up and filled out a lot. They spread very quickly too which was a nice surprise after seeing that our 2 small plants didn't cover the area as much as we hoped initially. We've even had to trim them back periodically.
Verbenas also attract butterflies... Eric snapped this with his phone one day - see the brown and yellow butterfly (kinda blurry but you get the idea).
We are no planting/landscaping experts but are very pleased with the pop of purple added to our lawn with some pretty low maintenance flowers!