Dates (Phoenix dactylifera) are the fruits of the Date Palm trees, and are above ground.
They grow above ground. It is a stem plant.
Above the ground
above.
A Swede grows below ground.
Below ground, just like a carrot.
Above ground. It is a flower.
Cabbage grows above ground.
Both
Below ground.
Above ground as the oat plant is like wheat.
No corn grows on a corn stalk above ground.
The potato tubers (potatoes) grow below the ground, but most of the potato plant (leaves etc.) grows above ground.