He Huan Pi, the bark of “gathered joy”

He Huan, “gathered joy”, comes from an observation: the tiny leaflets of the silk tree, Albizia julibrissin, fold together in pairs at dusk and open again at dawn. Hence its other names, “the one that closes at night” and “dusk”; the physicians of old saw in this gesture a kinship with that of the spirit withdrawing in the evening. The tree owes its Western name to its downy flower heads, with long silky stamens tipped with pink. The trunk bark is collected from summer to autumn; Hubei is the leading producing region. A saying pairs it with the daylily: “the daylily makes one forget sorrow, the albizia dispels resentment”.

Loosening what constrains, calming the spirit

In Traditional Chinese Medicine, the bark is neutral and has a single flavour, the mildest of all: sweet, which supplements and relaxes what has tightened. It weighs on neither side, which sets it apart from the heavy, mineral substances that tradition uses to anchor the spirit: this one anchors nothing, it loosens. It enters the Liver, which ensures the free flow of Qi, and the Heart, which houses the spirit. Its sweetness relaxes the constraint on Liver Qi while it calms the Heart; once Heart Qi is calm, says a classical text, the spirit finds its own course again.

A slow, cumulative bark

The oldest work of the Chinese pharmacopoeia describes it in a line that has become famous: it brings the Heart and the will into accord, and makes one joyful and free of worry. Tradition calls it gentle and cumulative: its Qi is slow, and it must be used generously and over a long period. With white peony, which nourishes Liver Blood, it suits times when constraint sets in on a background of insufficient Blood. Where jujube seed nourishes, the bark unblocks. Modern research is looking in particular at its triterpenoid saponins.

Key benefits

Calm Shen

Sweet and neutral, the bark enters the Heart, which houses the spirit, and calms the Shen without weighing it down.

Serene mood

By relaxing the constraint on Liver Qi, it improves mood; the ancients said it could make one joyful and free of worry.

A spirit that settles in the evening

Like its leaflets folding at dusk, it helps the spirit wind down at the end of the day.