Seed & division are the main methods of propagation..... but I have had some luck using 0.1% IBA (Rooting hormone) stuck in well drained soil 7 mist ... rooting took 10-30 days

before i killed all of mine on purpose ... i noted that they seeded three times a year ... hence the term invasive ...

i would plant 2 or 3 in a flat .... and let them seed themselves.. and i bet by next year .. you will have a flat full of them ...

they are weeds.. and i would bet you will have no problem with them in the flat over winter... if left on the north side of a building ...

if you are lacking success in replicating a weed [just my opinion] .. then you are over-thinking it all ...

GOOD LUCK!!!!! . ken

i used to weed my beds.. by throwing everything over my shoulder.. and at the end of the day .. just mowing it all into the grass ... worked great for everything..

except the violas ... which rooted themselves into the lawn after being mown ... then the chemicals came out ...

what a nightmare ... lol.. ken

it seems to me that some violas (like the common violets) are invasive, but others seem to produce few if any babies.