Analysis of Planted sentinels

Plants are in all intents and purposes sentient
And any serious observation will prove it so
But how in God's name do they 'think'?
And do they have a brain of sorts?
Will we ever hold a conversation with them?
Can they be considered as true aliens?

Are they planted sentinels
Out to spy on the alien race of man?
Or are they alien scientists
Out to pick and prod the animalistic man
By changing the diet and weather
And observing the change in chemistry?

Or are they wooden Trojan horse conquerors
That fooled us at the very dawn of life
And made us into their cultivar slaves
By making us completely dependent
In our core needs of diet, fuel and housing?

Or they are simply our strange symbiotic siblings
From our dear mother nature
Born dumb and slow of thought
They silently and patiently provide us
And born with rigid limbs
They unmovingly stand with us

In all our needs