In Du Mu's Wei Zihua, "Peach and plum are speechless" means that the peach and plum are unknown, but it also means praising the peach and plum. Why is it the contrast between Wei Zihua?

Autumn dew in Xiao Ying is a new branch, which does not occupy most of the spring in the garden.

What happened to peaches and plums? They laugh at sunny people in the wind.

In summer and autumn, crape myrtle blossoms, peaches and plums are gorgeous and have disappeared. This sentence uses peaches and plums to set off the uniqueness of crape myrtle.