Analysis of In a London Square

Put forth thy leaf, thou lofty plane,
East wind and frost are safely gone;
With zephyr mild and balmy rain
The summer comes serenly on;
Earth, air, and sun and skies combine
To promise all that's kind and fair: -
But thou, O human heart of mine,
Be still, contain thyself, and bear.

December days were brief and chill,
The winds of March were wild and drear,
And, nearing and receding still,
Spring never would, we thought, be here.
The leaves that burst, the suns that shine,
Had, not the less, their certain date: -
And thou, O human heart of mine,
Be still, refrain thyself, and wait.