Microseason: Paulownia Begin to Fruit

SUMMER

GREAT HEAT

PAULOWNIA BEGIN TO FRUIT

22 - 27 July

Great Heat. The hottest sub-season of the traditional microseasonal calendar has arrived. For the next two weeks, we are said to experience peak heat. If Small Heat, is the rehearsal, then Great Heat is the live performance. The season is marked when the purple flowers of the paulownia tress give way to hard-shelled fruit across the countryside.

Kiri is the lightest of Japan’s domestic timbers, yet it offers durability, flame resistance, and natural pest repellence due to its high tannin content. The wood is known for its low moisture permeability and dimensional stability, making it ideal for storing valuable documents and crafting cultural objects such as géta footwear, ceremonial masks, koto string instruments, and tansu chests. Paulownia wood chests were historically gifted to daughters upon marriage. The custom of planting a kiri tree at a girl’s birth, then harvesting it for her bridal gift was practiced nationwide well into the 1900s.

Kiri is a recognized material for ten government-designated traditional crafts and over forty regionally-designated ones. Not only is kiri used for craft ware but also seen used for the handles of saws and light tools, its tactile warmth and resistance to splitting makes it an imperative material for tools.

The tree’s distinctive leaves and blossoms are stylized into the go-shichi-no-kiri crest, used in imperial and national iconography. The idea that the mythical phoenix alights only on kiri trees gave rise to its status, particularly in Chinese and Japanese court cultures.

The kiri’s flowering period peaks in May, with upright bell-shaped blossoms ranging from 5 to 6 cm in length. The lavender flowers bloom at the highest branches, often out of view from ground level, their scent attracting large pollinators like carpenter bees. And when Great Heat arrives the petals begin to fall, giving way to camel-colored fruit buds which carry seeds and serve as next year’s flower bases.

While large-scale kiri cultivation has become rare, production remains concentrated in the Tohoku region where both climate and traditional knowledge support healthy growth. In Akita, kiri forestry is integrated with community education, volunteer forest work, and cultural preservation.

Like many other trees, when kiri feels it is endanger, it will generate another tree from its root system. We benefit and learn from its natural instinct to survive.

Photo credit: Akita Forest School