Ok, so lets just say it and get it over with..
NO! Just NO!
You should not replace sunflowers for corn in three sisters!
Grow the sunflowers on their own with a ground cover between then, that’s fine..
DO NOT, repeat do not believe the books that say, you can just replace them in the three sisters garden..
The sunflowers that are planted by themselves, are doing great.. they are huge and rocking it, the sunflowers that are interplanted with cucumber plants far enough between the plants that they don’t effect each other, are doing great..
The hills that where interplanted with squash, beans and sunflowers.. are a huge failure!
Massive! unbelieveable failure..
Its been a wonderful garden year, and just to prove the point, if I take the unproductive plants out of the hills and away from the sunflowers, they recover and produce like mad, while the ones left, are stunted and produce poorly..
If you are doing Three sister hills, use corn! Grow the sunflowers in their own rows..