Practical
Plants

Petasites japonicus

Sweet Coltsfoot

No photo available

Taxonomy and growth

Life cycle
perennial
Growth rate
vigorous
Height
0.6 m
Spread
1.5 m
Fertility
self sterile
Flower type
dioecious
Pollinators
Insects

Uses

Edible uses

Leaf stalks - cooked and used like rhubarb[1][8][14][4]. The stems can be up to 1.2 metres long[2]. They can be boiled and seasoned, pickled and used in winter soups or preserved in miso[6]. They can be boiled, dipped in cold water then peeled and baked - they have a pleasant fragrant taste[10]. Flower buds cooked or used as a flavouring[1][12][14][16][3]. A slightly bitter yet agreeable flavour[4][10], they are much prized in Japan[6]. They can be eaten whilst still green with miso or boiled down in soy sauce[6]. The young flowering stems can be eaten cooked[10].

Plant part
Flowers
Plant part
Stem

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

The plant (though the exact part of the plant used is not specified) is antiasthmatic, antispasmodic, expectorant and poultice[5]. A decoction is used in the treatment of chronic coughing and pulmonary 'deficiency', laboured or difficult breathing and asthma, constant sputum formation and pulmonary tuberculosis[5].

Product or use
Antiasthmatic
Product or use
Antispasmodic
Product or use
Expectorant
Product or use
Poultice

Material uses

The leaves of the sub-species P. japonicus giganteus are used as umbrellas by Japanese children[7]. The leaf stalks can be used as walking sticks[10]. Plants can be grown as ground cover in damp shady places[10]. They are too invasive for most gardens and should only be used where they have plenty of room[11].

Ecology and functions

Ecosystem niche
Soil surface

Environment

Range
E. Asia - China, Japan, Korea. Naturalized in Britain.
Habitat
Moist woods and thickets[15].
Light
full sun
Shade tolerance
permanent shade
Water
high
Hardiness
Zone 5+
Soil textures
sandy, loamy, clay
Soil pH
acid, neutral, alkaline
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

Seed - we have no information on this species but suggest sowing the seed in a cold frame as soon as it is ripe or in early spring. Only just cover the seed and do not allow the compost to dry out. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer. Division succeeds at almost any time of the year. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer.

Cultivation

Succeeds in ordinary garden soil[1], but prefers a deep fertile humus-rich soil that is permanently moist but not stagnant, succeeding in shade, semi-shade or full sun[9]. Requires a moist shady position[7]. Plants can be grown in quite coarse grass, which can be cut annually in the autumn[13]. A very invasive plant, too rampant for anything other than the wild garden[7][9]. Its roots are very difficult to eradicate[9]. The sub-species P. japonicus giganteus has huge leaves up to 1.5 metres across on stems 2 metres tall[7]. It has a poorer flavour than the species type[10]. Sometimes cultivated in E. Asia as a food plant[1][15]. Dioecious, male and female plants must be grown if seed is required.

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

    ↩1↩2↩3↩4

  2. RHS. The Garden. Volume 111. Royal Horticultural Society 1986-00-00

    ↩

  3. Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976-00-00

    ↩

  4. Brooklyn Botanic Garden Oriental Herbs and Vegetables, Vol 39 No. 2. Brooklyn Botanic Garden 1986-00-00

    ↩1↩2

  5. ? A Barefoot Doctors Manual. Running Press ISBN 0-914294-92-X

    ↩1↩2

  6. Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990-00-00 ISBN 0-9628087-0-9

    ↩1↩2↩3

  7. Phillips. R. & Rix. M. Perennials Volumes 1 and 2. Pan Books 1991-00-00 ISBN 0-330-30936-9

    ↩1↩2↩3↩4

  8. Hedrick. U. P. Sturtevant's Edible Plants of the World. Dover Publications 1972-00-00 ISBN 0-486-20459-6

    ↩

  9. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3

  10. Larkcom J. Oriental Vegetables John Murray 1991-00-00 ISBN 0-7195-4781-4

    ↩1↩2↩3↩4↩5↩6

  11. Thomas. G. S. Plants for Ground Cover J. M. Dent & Sons 1990-00-00 ISBN 0-460-12609-1

    ↩

  12. Sholto-Douglas. J. Alternative Foods.

    ↩

  13. Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990-00-00 ISBN 0 460 86048 8

    ↩

  14. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩1↩2

  15. Ohwi. G. Flora of Japan. (English translation) Smithsonian Institution 1965-00-00

    ↩1↩2

  16. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

    ↩

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