Blake's Tree

Genesis 2[9] And out of the ground made the LORD God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil.
Genesis 3
[22] And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:
[23] Therefore the LORD God sent him forth from the garden of Eden, to till the ground from whence he was taken.
[24] So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.

When he was a young boy Blake reported that he had seen a tree filled with angels; one of his parents disapproved.

In Marriage of Heaven and Hell:
"A fool sees not the same tree that a wise man sees." 

"For the cherub with his flaming sword is hereby commanded to leave his guard at tree of life."

A Poison Tree:
"I was angry with my friend:
I told my wrath, my wrath did end.
I was angry with my foe:
I told it not, my wrath did grow.
And I watered it in fears,
Night and morning with my tears;
And I sunned it with smiles,
And with soft deceitful wiles.
And it grew both day and night,
Till it bore an apple bright.
And my foe beheld it shine.
And he knew that it was mine,
And into my garden stole
When the night had veiled the pole;\
In the morning glad I see
My foe outstretched beneath the tree." 

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From the Book of Ahania:

"For when Urizen shrunk away

From Eternals, he sat on a rock
Barren; a rock which himself
From redounding fancies had petrified
Many tears fell on the rock,
Many sparks of vegetation;                             
Soon shot the pained root
Of Mystery, under his heel:
It grew a thick tree; he wrote
In silence his book of iron:
Till the horrid plant bending its boughs    
Grew to roots when it felt the earth
And again sprung to many a tree.
 Amaz'd started Urizen! when
He  beheld  himself compassed round
And high roofed over with trees             
He arose but the stems stood so thick
He with difficulty and great pain
Brought his Books, all but the Book
Of iron, from the dismal shade
The Tree still grows over the Void
Enrooting itself all around
An endless labyrinth of woe!
The corse of his first begotten          
On the accursed Tree of MYSTERY:
On the topmost stem of this Tree
Urizen nail'd Fuzons corse
(Erdman 86-87)

For the tree of Mystery go here.