What does this poem mean? the literary techniques and the main idea?

“Fall, leaves, fall: die, flowers, away,” by Emily Jane Bront?



Fall, leaves, fall; die, flowers, away;

Lengthen night and shorten day;

Every leaf speaks bliss to me

Fluttering from the autumn tree.



I shall smile when wreaths of snow

Blossom where the rose should grow;

I shall sing when night's decay

Ushers in a drearier day.

What does this poem mean? the literary techniques and the main idea?
It's literary technique I would say is rhyming. It's talking about the end of Autumn is welcoming the new season of Winter.