Veronica allionii

Flower spikes of purple-blue flowers appear in July in our zone 3 garden. 

I don't particularly care for the Veronicas which have the purple flower spikes. This is the only one of that group of plants I've seen which I'm interested in growing.

Useful as a groundcover, and looks good in a rock garden.

Hardy to zone 2.

Flower spikes grow 4" to 6" in height; will form a patch 12" wide in couple of years.

Glen's rating:  6.