Arisaema heterophyllum Seeds | Chinese Jack-in-the-pulpit
LATIN NAME: Arisaema heterophyllum
COMMON NAME: Chinese Jack-in-the-Pulpit
Plant Profile
Arisaema heterophyllum is a woodland aroid with a leaf that looks like a hand and a flower that looks like a hooded figure. The leaf is solitary, divided into many narrow leaflets that radiate from a central point, and it stands about eighty centimetres above the ground. The inflorescence is a green and purple spathe curled around a spadix, and it appears in late spring, often before the leaf is fully open.
The species grows in damp, shady forest in eastern China, Korea and Japan, in soil rich in leaf mould. It is one of the larger Chinese arisaemas, and the genus is diverse in the mountains of south-west China, where many species are grown by collectors for the strange flowers.
Science & Biotechnology
Arisaema is one of the aroids that change sex with size. A plant stores energy in a corm, and the size of the corm in a given year decides whether it produces male flowers, female flowers or none at all. A small corm produces male flowers, which are cheap; a large one produces female flowers, which cost more because they have to make seed. If the season is bad the plant may revert to male or skip flowering entirely.
The inflorescence is a trap for small flies. The spathe forms a chamber, the spadix gives off heat and a fungal smell, and the insects are held overnight and released the next day with pollen. The plant is also poisonous: all parts contain calcium oxalate crystals and a protein that causes intense irritation, and the corm is the most toxic part.
Uses & Benefits
In Chinese medicine the corm is used externally for swellings and for snakebite, and it is applied as a paste rather than taken internally, because of the oxalate. The plant is known as yi ye ban xia or as tian nan xing in some districts, and the processed corm is used in formulas for phlegm. The raw corm is dangerous and should not be handled without gloves.
The plant is grown by collectors for the foliage and the strange inflorescence, and it is sold in the woodland-garden trade. It is not a food plant, and the berries that follow the flower are poisonous to people and to pets.
Growing from Seed
The seed dies within weeks of leaving the berry, so sow it in the same autumn. Clean it from the berry, sow it in a moist, peaty mix, and keep it at 18 to 20 degrees; germination is in a few weeks, and the seedling forms a small corm in its first year. Offsets from the mother corm are easier.
The plant wants deep shade, a humus-rich soil and constant moisture, and it grows well under deciduous trees. It is hardy to about minus fifteen if the corm is deep enough, and it should be mulched with leaf mould in autumn. Mark the site, since the plant dies down in summer and is easy to dig by mistake.
Our Take
A collector’s woodland plant with a flower worth kneeling for, and a corm that should be handled with gloves and never eaten.
Related Reading
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