Sunflowers would appear in the desert/new lava-themed island durring summer. They'd disappear when autumn begins. Sunflowers would cause players to quickly overheat. In order to dig them up you need to use Ice on them 3 times.
You'd be able to plant them only in a special 'Sunflower Pot' which would require Drgonfly's scales.
After planting a Sunflower in that pot and fertilizing it with ash (yes like coffee bushes in Sw) it would create a 3 tile square zone where plants can grow durring winter. After every 4 days you'd need to fertilize it again.
Thoughts?