With the passage of the summer equinox, the rising heat brings the silk trees, those handsome, troublesome plants known as mimosas, to the end of their blooming season.

Here's a tree that was encouraged by early Far Eastern royalty as representing the tree of heaven. Now, with July almost here, mimosas are coming to the end of their spectacular pink-blossoming days.

These are short-lived trees, and not very tall -- about 30 feet. In the spring they sport great masses of flowery soft pink pom-pom fluffs that stand in delicate contrast to the powder blue skies. Like them or hate them, mimosas are spectacular.

The Chinese, noting the tree's fern-like leaves that close in the evening, offered the name hehuan, meaning leaves "that shut happy" -- symbolizing a happy couple in bed. Today most gardeners refer to this same tree as mimosa, a name thought to have been derived from Portuguese "formosa" meaning "of great beauty."

However, not everyone can find room to fully appreciate the mimosa's uncommon attributes, even though it is unequaled as sanctuary for hummingbird and butterfly. Mimosas are considered weed trees. Many people concerned about invasive plants urge that they not be planted, because they crowd out native species.

One reason for that is their habit of dropping thousands of long-lived seeds that produce hundreds of offspring.

That is, when it comes to keeping future generations in check, the tree of heaven becomes the devil's own.