I wanted to see if I could find the botanical name, and found myself in the middle of a controversy. This web site, calls it Viola cornuta (Violaceae), citing it's source as Wildseed Farms, near Fredericksburg, Texas. Wikipedia calls it, Heartsease (Viola tricolor), but there are detractors, see the discussion page, where someone claims, heartease is just bi-coloured. Acknowledging the weaknesses of Wikipedia, and personally having had visited Wildseed Farms, I am gonna have to go with Wildseed on this one.
Of further interest is the comment from Wildflower Information.org, which states Johnny is not invasive. I planted Johnny Jumpups here well over 10 years ago. It no longer grows where I planted it. It "pops up" all over the property now. I have loners in the flower beds surrounding the house, here and there. This photo was taken down by the pond, and currently is the largest group of Johnny's I have.
My Johnny Jump Ups continue to spread around the yard, delighting me with their small jolt of color. They are what I call "volunteers", as they volunteer here and there, where ever they feel they are "needed".
They always make me smile.