Luoyang spring came a little late, full of spring.
Poplar leaves will be black and peach blossoms will not be thin.
Peeping under the eaves, competing in the crowd and flying in the forest.
Only when there is a traffic jam will clothes get dirty.
Look at the context, "poplar leaves will be dark and peach blossoms will not be thin." In order to write a landscape sentence, it describes the unique scenery of nature when flowers fall in late spring. The leaves of poplars are turning black and peach blossoms are falling, but the flowers on the branches are not rare. It paves the way for the sympathy of the frontier fortress soldiers at the end of the whole poem, which embodies the poet's keen observation and extraordinary pen power.
Personal views are for your reference.