This is the Asian species, spread from Korea across China to E.Russia, but not Japan. As with many herbaceous Berberidaceae, growth in spring is very rapid and the plant bursts through the soil flowering early. It quickly develops attractive foliage, which is rounded and deeply divided (though not to the extent of the other species, the American “Twinleaf”, Jeffersonia diphylla).
Numerous stalks of up-facing blue-lavender, chalice-shaped flowers cover the plant. The flowers are borne on stems of about 10-12 cm, the plant is long-lived and slowly clumping and can reach twice this across, with dozens of stems. At that size it demands the attention of any gardener. The fruits which follow are green, pear-shaped capsules, which in this species split laterally, from the top.
Likes well-drained, slightly limey or circum-neutral, humus-rich soils. Said to grow over limestone in Asia, but I have no confirmation of this. Half-shaded woodland type sites are best.