If you transplant some, get them while they are still really small (seedlings) and take a lot of attached soil with them. Basically, shovel them up and then replant them in a hole that is shaped the same as that shovel of soil. They don't like to be transplanted and when larger they will usually croak.
Also, they are susceptible to the Impatiens Downy Mildew that is taking out the related bedding plant, Impatiens walleriana.
Sadly, we have the Impatiens Downy Mildew here so I don't have any Impatiens capensis.
Hummingbirds adore them!
