Your lobelia is doing well and the single imps are doing well but your doubles aren't? Impatiens can actually stand some sun. I have found doubles to be a lot more difficult than the singles. They will drop blooms and blossoms readily with any change in environment. 90 degree weather is tough on impatiens as well.

If the lobelia, singles and doubles are in the same pot and the lobelia and singles are doing well then I would just keep doing what your doing. Doubles are a lot more difficult - it may be too damp for them... Every year I get pulled into the doubles because they have a beautiful varigated double bloom imp I can't resist - but it never does as well as the singles.

I notice you posted this a while ago - what have you done and what have they been doing since?

Hi, thanks for the answer! I've just been leaving them as they are. The lobelia and singles are doing great. The doubles still look really nice as the stems and leaves are pretty and green, the blooms just droop down below so you can't see them. All in all the whole pot is doing pretty well I just wish I could make the doubles show their face, they're so pretty.