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Polymnia edulis - Wedd.

Yacon Strawberry

Author	Wedd.	Botanical references	1
Family	Compositae	Genus	Polymnia
Synonyms	Polymnia sonchifolia - Poepp.&Endl. Smallanthus sonchifolius - (Poepp.&Endl.)H.Rob.
Known Hazards	None known
Range	S. America - Colombia, Ecuador, Peru in the Andes.
Habitat	Not known
Edibility Rating	4 (1-5)	Medicinal Rating	0 (1-5)

Physical Characteristics

Perennial growing to 1m by 0.6m at a fast rate.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and can grow in nutritionally poor soil. The plant prefers acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It requires moist soil.

Habitats

Woodland Garden; Sunny Edge; Cultivated Beds;

Edible Uses

Edible Parts: Leaves; Root.

Edible Uses: Drink; Sweetener.

Root - raw or cooked[1, 22, 46, 61]. When first harvested, the root can taste somewhat starchy[K], but it soon becomes sweet, crisp and juicy and is delicious eaten raw[196, K]. The flavour is further improved by exposure to the sun although some of the crispness will be lost[97, 183, K]. The root can be eaten like a fruit or diced and added to salads[183]. The skin has a somewhat resinous taste so it is usually removed[196]. The cooked root retains is sweetness and crispness[196]. Individual roots can weigh up to 500g[196]. The nutritional value is low because the root contains a high quantity of inulin, a carbohydrate that the human body cannot utilize[196]. The grated pulp of the root is squeezed through a cloth to yield a sweet refreshing drink[183]. This juice can be concentrated to form dark brown blocks of sugar called 'chancaca' in S. America[183, 196]. Leaves and stems - cooked as a vegetable[183, 196]. They contain 11 - 17% protein, dry weight[196].

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

None known

Other Uses

None known

Cultivation details

For best results, this plant requires a warm position in a deep rich soil[1], though it survives even when growing in poor soils[196]. Plants are fast-growing[196]. In S. America, they succeed in areas with annual rainfall varying from 900 - 3500mm[196], though are likely to succeed with less rain in temperate zones. The yacon is cultivated for its edible tuber in the Andes, and is sometimes used in sub-tropical summer bedding schemes in Britain, though it is not very hardy[1]. The top growth is killed back by frost but the tubers can tolerate at least light frosts[196]. Plants are unaffected by day-length and so can produce good yields of roots in temperate zones[196]. One report says that plants take 6 - 7 months to produce a crop from planting out[196], though on our Cornwall trial ground they have cropped quite well with a 5 month growing period[K]. The roots are brittle and must be harvested with care to avoid damage[196]. Yields of 38 tonnes per hectare have been recorded in South America[196], whilst yields of over 2 kilos per plant have been achieved outdoors in Cornwall[K]. The harvested roots can be stored for several months[196]. Plants have not been selected for flavour or yield, some roots can be exceedingly sweet whilst others are fairly bland[196]. Plants might be useful in agroforestry because they succeed under trees[196], though in the relatively sunless climes of Britain the plants are not likely to do well in the shade of trees[K].

Propagation

Seed - sow mid winter in a warm greenhouse and only just cover the seed[1]. Prick out the seedlings into individual pots as soon as they are large enough to handle and plant them out after the last expected frosts. Consider giving them some protection such as a cloche until they are growing away well. Plants do not usually produce flowers in Britain and therefore seed has to be obtained from other countries[K]. Division in autumn. The plant forms 2 distinct types of tuber. Large tubers, usually on thin roots 2 - 5cm long, are used as storage organs and do not have the capacity to form new shoots. These are the tubers that are usually eaten. Smaller tubers are formed in a cluster around the stem. These form the shoots for the following year's growth and so are the ones that should be stored. Dig up the plants in the autumn once the top growth has been cut down by frost. Remove the large tubers for food, cut the main stems back to about 10cm long and store these stems with their cluster of small tubers in a cool frost-free place. Do not let them dry out. Pot them up in early spring in a greenhouse. When they come into active growth divide each cluster into individual shoots with their tubers attached and repot these. Plant them out in late spring after the last expected frosts[K]. Cuttings of basal shoots in early spring in a warm greenhouse[1]. Harvest the shoots with plenty of underground stem when they are about 8 - 10cm above the ground. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.

Links

This plant is also mentioned in the following PFAF articles: Alternative Root Crops.

References

[K] Ken Fern
Notes from observations, tasting etc at Plants For A Future and on field trips.

[1] F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).

[22] Sholto-Douglas. J. Alternative Foods. 0
Not very comprehensive, it seems more or less like a copy of earlier writings with little added.

[46] Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959
An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.

[61] Usher. G. A Dictionary of Plants Used by Man. Constable 1974 ISBN 0094579202
Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.

[97] Towle. M. A. The Ethno-Botany of Pre-Columbian Peru. 0
A very interesting book covering quite a lot of information on plant uses in S. America although many of the plants are not suitable for temperate areas..

[183] Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990 ISBN 0-9628087-0-9
Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.

[196] Popenoe. H. et al Lost Crops of the Incas National Academy Press 1990 ISBN 0-309-04264-X
An excellent book. Very readable, with lots of information and good pictures of some lesser known food plants of S. America.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

Brenner's Experience on Growing Yacons

Brenner Wed Oct 23 17:56:13 2002

This article originally appeared in the Jan 1998 edition of the Friends of PFAF newsletter.

What can I say about this plant? I grew some last year in tubs in the garden (because of an impending move) and I was constantly asked if they were Triffids!

The Yacon, I believe, comes from South America. It is a tuberous plant topped by enormous leaves (in fact, although the leaves have a different shape the span is similar to rhubarb), the stems etc. are quite hairy. The tubers, when harvested, weighed in at 14lbs (6.3 kilos) and that from just 3 plants. Had I been able to grow them in the ground then I am sure that the yields would have been even higher! The overall yields were very good, better than I have ever done with potatoes. I did make sure the plants were kept well watered and once a week gave them a liquid feed of either comfrey or diluted urine.

The top growth was cut down by the first heavy frosts of the autumn, and this would have been the best time to harvest the tubers. However, at this time I was busy moving home and so the plants were left in the tubs until January. Most of the tubers were a very good size and in good condition. They have stored well and I am still eating them now (late March). In fact, I felt that they kept better by being left in the pots and certainly the small top tubers (the ones that are used to grow the following year’s plants) were already sprouting when the plants were dug up. In the previous year all my top tubers had rotted away whilst in store.

I am planting these small tubers in pots at the moment and have managed to get 10 - 12 plants from each plant I grew last year.

Yacons are delicious to eat either raw or cooked. They are crisp and juicy with a lovely sweetness, in fact they are much more like a fruit than a root crop. I like to peel them thinly (this peel is rather aromatic and I am not too keen on it) and then cut them into thin slices and add them to salads just before serving. The tubers tend to pick up the flavours of foods they are cooked with and I find their crunchy texture goes very well in a stir fry. They go well with avocado pears and a squeeze of lemon and I like adding them to a tomato and basil salad where they add a nice crunch.

I could go on about ways to eat it, but you must suit yourselves. I’m told that you can boil and bake them, though I have never tried them this way. Stir-frying with ginger, garlic, onions and mushrooms, plus some mustard and stock with a nut crumble topping is gorgeous.

I must stop now or I’ll get totally carried away and there won’t be room for anything else in this newsletter. Next time I write it will be a diary on my almost virgin garden and my plans, along with a recipe using PFAF perennial plants. Until next time.

Brenner

Polymnia edulis

Robert P. Nederpelt Fri Nov 29 12:29:30 2002

Link: IPGRI Andean roots and tubers: Ahipa, arracacha, maca and yacon PDF file available

Polymnia edulis

Carol Tue Nov 11 15:33:50 2003

I was intrigued by the description that I saw for this plant in the Nichols Farm Nursery catalog (Washington state, U.S.)and decided to try it. I live in SW Pennsylvania, USDA zone 5. The 6-8" tall potted plant arrived safely (I was impressed with the excellent packing job!), but too early for planting out in my area, so I kept it under lights with my other seedlings until I could harden it off and get it into open ground. We had an unusually cool and quite rainy growing season this year, and the plant got off to rather a slow start. Once established, however (on the west side of my red brick house, which gave it the tropical heat I felt it would appreciate when the sun did shine!) it quite quickly grew to about 4 feet before a severe wind/rainstorm broke off the top foot or so. The side shoots took over and continued to grow enthusiastically, however, and withstood several light frosts (the first about 2 weeks early for my area, on Oct. 1) with only minor blackening of the more exposed leaves, which were quite exotic-looking and drew comments from visitors over the summer. I left it to enjoy a long, mild Indian summer period until truly severe cold was imminent (28F, on Nov.7) and chopped the ,woody stalk off with a machete.(!) Digging the tubers was quite an eye-opening experience, as I found large, somewhat intertwined tubers the size of large yams, but with the smooth skin the texture and color of white potatoes. I found they had the taste and texture, however, of Jerusalem artichokes, and the smaller tubers immediately beneath the stalk were much smaller & knobby exactly like the J. artichokes. After washing & weighing the harvest, I found that my solitary plant yielded about 4 1/2 pounds of edible tubers, with enough of the small "planting tubers" to give me at least 2-3 dozen new plants next year if I wanted that many (I don't have room!). Thanks to the info in the entry above, I will plant some out in pots in my cold frame, but I also will leave some in my refrigerator, just to see if they will remain in good condition for planting, and also pot some tubers and keep them in the fridge until late winter. They already look ready, willing, and able to grow, had I the proper climate! Since I find them so similar to J. artichokes, I have enjoyed them raw & added at the end to a stir-fry, but have no intention of cooking them otherwise, as I never cared for cooked J. artichokes. Seems to me that this relatively unknown plant would be a valuable addition to any temperate climate garden. Its yields would make excellent nutritious and inexpensive livestock feed for some animals as well, I should think.

Polymnia edulis

Professor Marshall A.C.A.Odii Tue May 22 2007

My visit to Schedewinbeke provided me an opportunity to visit a man who is close to nature and who does things in slightly different way. When I ate the tuber of the Yacon crop which I saw for the first time, I immediately liked the crop and began to suspect that it might have some medecinal impact on humans. I would like to see if I could grow the crop in a tropical environment such as Nigeria Thanks Professor Marshall A.C.A.Odii Department of Agricultural Economics Federal University of Technology Owerri PMB 1526, Imo State, Nigeria

Polymnia edulis

Al Kapuler Sun Feb 10 2008

Mabberley lists Yacon as Smallanthus sonchifolia. The inulins are built from glucosyl-fructose (sucrose) with additional fructoses being added on inceasing the size. Average chain length 5 fructoses. Chicory has inulins with chain length of 25-30; the grasses have inulins with chain length of 200. So yacon has inulins that are easier to digest. Yacon also has free amino acids in the juice (work of Kapuler and Gurusiddiah decades ago). Steve Spangler brought yacon from South America (probably Peru) in the mid 1980's. http://ps.88uu.com.cn. PeaceSeeds.com --

Alternative Root Crops

john andreae Thu Mar 27 2008

Does anyone know where I could purchase yakon tubers in the UK? thanks john

Polymnia edulis

GERALDINE Tue Aug 5 2008

CAN WE MAKE SOAP OUT OF YACON LEAVES?

Polymnia edulis

NIGEL MURISON Wed Oct 7 2009

Nigel Murison 7 Oct. 2009 I will have Yacon reproductive tubers available this year(2009) email: nigelsgreennotebook@hotmail.com

Polymnia edulis

Nigel Murison Thu Oct 15 2009

I have Yacon reproductive tubers available this year (2009).email: nigelsgreennotebook@hotmail.com U.K.only.

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