Phoenix Flowers.

[Maou]

I am on day 6 in my current game and no Phoenix Flowers have spawned. I am kind of locked out of the game at this stage.

[Echidna]

move fog further and destroy/harvest vegetation to clear space for phoenix flower to grow

[Azure]

I agree Maou. I just had two games go the same way. One where no trees spawned after being cut down, and harvested the entire area clean and still no tree spawned. The next game had no smoke stick spawning.

[Jay]

Smoke stick and phoenix flowers seem more likely to spawn on the 2nd and 3rd distance of fog than up close to the school.
Push fog back, clear the spawn spots ("destroy" plants that are growing that you don't need, if you have to).
Those plants will come.

[Prometheus]

Make sure to use both staff and the ghost for the fog ritual. Also to repeat what others are saying, push the fog further, phoenix flowers have a minimum spawn distance from the school.