There once was a boy who loved butterflies. He’d chase them throughout town, catching them with his net. He would admire their lightness and beauty, then release them back into the wild.
But every time they fluttered away, his heart grew sad. Without them, his world was black and white, concrete and cruel.
One day, he had an idea: what if he kept the butterflies? Then he would never have to search for beauty again. He would have it at his fingertips forever.
That morning he loaded his backpack with jars and grabbed his net. By the time the sun set, his containers were full. He had monarchs and swallowtails, painted ladies and zebras, a red-spotted purple and common buckeye.
The boy skipped home. When he got there, he let the butterflies loose.
The next morning he awoke with a butterfly on top of his nose. Butterflies kissed his eyelashes and caressed his toes.
But the boy couldn't stay in his room forever, for he had a life to live outside those four walls. So he put the butterflies back in the jars.
When he returned, he raced straight for the containers. But when he opened them, nothing happened.
“What’s wrong?” he thought. “Why aren’t they flying?”
He realized he had forgotten something important: the butterflies needed food.
That night, he grabbed scissors and sneaked into his mother’s garden.
The next morning he awoke to his mother’s screams.
I really like your idea for this story, I'd like to know why his life is colorless without the butterflies in it. I also think you need to use another flower besides lilacs, simply because lilacs usually grow in such a plentiful way that snipping a few wouldn't even be noticed, let alone cause a mother to shriek. Perhaps some prized lilies - maybe that's the conflict, that the Mother spends more time in her garden with her flowers than making the little boy's life fun and and interesting and colorful.