I don't know what the Harley/Trinity plant is meant to be because "viola" was a generic term for a lot of bluish-purple plants, but in terms of general characteristics (narrow leaves at 90 degrees, flowers at the top) it LOOKS like Linum. Some species of Linum have long narrow leaves (especially Linum angustifolium) and Linum comes in numerous colors, particularly blue/violet, yellow, and white. Linum was frequently included in medieval herbals.
Another possibility is Gentiana. Some species have long narrow leaves, blue flowers at the top in little groups. The wild varieties are not as densely leaved as the garden varieties. Several species of gentian were called "viola". It's usually blue or blue-violet, but it also comes in white and occasionally yellow:
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The leaves look like ironweed (Vernonia), but that's a North American plant. Many gentians are circumboreal.