May 27, 2018

Japanese Rough Potato (Metaplexis japonica)


A very rarely cultivated in Europe hardy perennial herbaceous climber (to 8m=27ft tall) from Japan, Korea and Russia. It belongs to Milkweed family (Asclepiadaceae).

        It is very cold hardy (to at least zone 6b) and can survive without mulching very strong frosts when established [even (- 25°C)=(-13°F) or less]. It creates annual fast growing stems, perennial rhizomes and numerous beautiful, medium size (showy, pale violet, hairy, odd-looking) flowers in racemes. Easily grows in any well drained soil, and half shaded to sunny spot. Flowers in the second year after sowing (about 15 months to first flowers). This is useful plant - Asiatic vegetable: young leaves can be eaten raw or cooked, young fruits - raw or pickled, long thin (about the thickness of a thick twine) rhizomes - cooked. Also poisonous plant (raw milk sap). It is also used in medicine (haemostatic, tonic, aphrodisiac etc.). The seeds' fluff can be  possibly used as a stuffing material for pillows etc. Climbers planted in the garden often move to neighboring areas (due to it has long creeping rhizomes which creates the shoots in other place every year) - hence the plant makes the impression of a wanderer - grows from another place every year and can cover very large area within a few years. There is very interesting a biology of flowers and pollination - odd-looking hairy flowers are pollinated by large night moths. Small insects (as mosquitoes, flies, beetles or medium size moths) are trying to get a nectar from flowers but they are too weak to take out the mouthparts from flowers and die trapped. The fruits are the follicles about 8-9cm=3-4 inch long which contain inside a fluff (with the seeds). They break and open in medium autumn and hang on die shoots to spring and they are gradually spreading the seeds.  Seeds should be sown surface (a light stimulates germination) in warm place inside in pots. Replant the seedlings outside in summer without root disturbance.
It has odd-looking flowers
They are very ornamental
The flowers trap and kill small or medium size insects
It even traping the mosquitoes
... and large flies
 
The young fruits
Ripening fruits
The dry fruits
The rhizomes are very long and not thick

There exists in China the second species of this genus -Metaplexis hemsleyana (called "hua luo mo"). If you have the seeds of it, or any other rare hardy asclepiad climber (Cynanchum spp., Matelea spp., etc.), please write to me.

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