As legend has it, the cross on which Jesus was crucified was made from a dogwood tree.
 God decreed that the dogwood tree would from that day
forth never grow large enough to be used to make a cross.
Thus, the dogwood tree is a small, under story tree.
      The flower of the dogwood has four petals which makes the shape of a cross.
     The center of the flower resembles the crown of thorns with bright red,
clustered fruit in the center representing the blood of Christ. 
     The dogwood blooms in April when Easter Sunday 
     marks the resurrection of Christ after the Crucifixion.

The Old, Old, Legend Of The Dogwood

Two thousand years ago, few trees in the Middle East were not big enough to construct anything.
  However, one tree was valued above the others for its thick trunk and fine, strong wood.When the
  Romans came to rule over Jerusalem, their government used this same timber to build the crosses
  for executing criminals. A group of workers were assigned to gather wood for the crosses. Before
   long, every Roman official knew the best wood came from these gatherers of execution wood, so
  those workers became popular.

   One day, the wood gatherers received a special request. An officer of the Roman court came and
  said, "The King of Jews is to be put to death. Deliver an extra-large cross made from your finest
  wood." So, a fresh tree was cut from the forest of the trees with thick trunks and fine, strong wood.
               An extra-tall (and extra-heavy) cross was quickly made and delivered.
   Three days after the death of Jesus of Nazereth, the chief wood gatherer got alarming news. "All of
  our finest trees are withering!" the messenger whispered. The wood gatherer hurried to the forest
  and saw that it was true.

   Several years later, the chief wood gatherer heard that, every spring, many people visited the old
 forest that had once made his job so easy. Despite his advancing years, he set out to discover why.
  He saw the remains of forest, now like a salty bottoms, with only a few trees still standing tall,
baked, lifeless and rotting.
 

    But what was this? As he drew closer, his feeble eyes could make out the people walking among
  thousands of beautiful, flowering bushes. Seeing one of his own workers there, the old man said,
 "No one could ever make a cross out of this twisted wood. Our finest tree has gone to the dogs!" He
 noticed the beautiful white flowers, each blossom looking as if it had been burned from the touch of a
     miniature cross. So...an old and beautiful legend has it that, at the time of the crucifixion, the
  dogwood was comparable in size to the oak tree and other monarchs of the forest. Because of its
  firmness and strength it was selected as the timber for the cross, but to be put to such a cruel use
   greatly distressed the tree. Sensing this, the crucified Jesus in his gentle pity for the sorrow and
   suffering of all said to it: "Because of your sorrow and pity for My sufferings, never again will the
   dogwood tree grow large enough to be used as a gibbet. Henceforth it will be slender, bent and
 twisted and its blossoms will be in the form of a cross -- two long and two short petals. In the center
 of the outer edge of each petal there will be nail prints -- brown with rust and stained with red -- 
and in the center of the flower will be a crown of thorns, and all who see this will remember.

Legend of the Dogwood in a Flash movie . . . here.