Oh yes, they will spread. They seem to be more annual in nature than the heart leaved violets. But have no fear, like any relative of the violet family, they will be spreading their seeds.

I'm sure you can try and transplant them any time. You can buy them in nurseries (violas) in the fall when pansies are sold.

Are you talking about the wild purple violets or the purple and yellow violas? The purple wild violets are very invasion. I've had the purple wild violets at another house in a shady spot and was soon waging war to remove them from my lawn. The others are sweet to have and I think, die out in the heat.
Debbs

Yes the wild purple violets are very invasive.. THey are my neighbors entire lawn.. They have spread to parts of my back lawn and now have found a few in my front lawn.. I don't mind them in the back with theshade, due to lack of growth back there but no way in my front..
Alison

OK, I'm thinking that they are indeed violas, not violets, the blooms are so small. The leaves are also not the heart shape of those invasive violets. Thanks for your enlightenment.

Probably Birdfoot Violas, they transplant easily but are a pain to get rid of. Kinda like planting Kudzu in your own yard!

Years ago I put a bunch in a hanging basket.(cause my wife loved them) The next spring I had about a hundred coming up all around where the basket had hung. When the seed pods dry they open like a shot and fling seeds everywhere. I now stomp or pull all I see.