Theory:

     The good old man humbly asked for the ashes. Though the covetous couple turned up their noses at him and scolded him as if he were a thief, they let him fill his basket with the ashes.
 
     On coming home, the old man took his wife into the garden. It being winter, their favourite cherry tree was bare. He sprinkled a pinch of ashes on it, and, lo! it sprouted blossoms until it became a cloud of pink blooms which perfumed the air. The news of this filled the village, and everyone ran out to see the wonder.
 
     The covetous couple also heard the story, and, gathering up the remaining ashes of the mill, kept them to make withered trees blossom.
Explanation:
 
Though the neighbours were wicked and impolite, the good old man remained humble to them and asked for the ashes of the hand mill. They treated him like a thief and scolded him. Though the bad old couple were corrupt-minded, they did not deny his request but gave him the ashes. The good old man was happy to get the mill ashes collected and returned home.

Then he called his wife and took her to the garden. They went near their favourite cherry tree, which looked bare without any leaves or fruits since it was winter.
 
Winter season in Japan.jpg
Winter season in Japan
 
Still, the good old man believed in his dream and had trust in the words of Muko's spirit. As a result, he sprinkled a handful of ashes on the withered cherry tree. Then, as the dog's spirit had stated in the dream, something miraculous occurred. The bare tree gave out cherry flowers which produced fragrance in the air. The news about the good old couple and the cherry tree had very soon reached the nook and corner of the village. Everyone gathered near the good old couple's garden to see the flowering tree during the winter.

When the wicked, greedy old couple heard about the fortune of the good old people for the third time, they decided to do the same thing. Since they gained nothing out of their first two greedy efforts, they become strongly desired and very soon collected the remaining ashes of the hand mill that's been burnt at their home. So they decided to make the withered trees blossom.
 
Meaning of difficult words:
 
S.No
Words
Meaning
1.
BareNot covered with leaves
2.
Thief Someone who steals something
    3.SproutTo grow or produce new leaves
4.
MeanUnkind and unfair
Reference:
National Council of Educational Research and Training (2007). Honeycomb. The Ashes That Made Trees Bloom (pp. 55-63). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.