In 2009, this small garden area was planted with one of the Super Elfins (?Coral). They remained true for the entire summer. This year, only begonias were planted in the same area. The next photo shows what grew this year from self-seeding.
Variability of Self Seeding Impatiens
mslehv, I wish I could answer your question but instead I have one of my own-will impatiens reseed themselves for me here in PNW. I'm thinking that we have similar conditions but I have never seen impatiens reseed. If they would I'd be glad to have them in whatever colors appeared. I think you're lucky.
Mine reseed prolifically along the sides of our homemade waterfalls. We get mostly the same ones we have planted in the past. I only buy colors I haven't seen each year, now.
But impatiens I have planted elsewhere don't reseed much, except in a steep situation. I assume the seeds fall down the little hill and rest at the bottom where it is moist and they come up the following year.