Yacon — A Newcomer from South America

All the way from South America, rather like Paddington Bear, comes my new favourite vegetable, Yacon, Smallanthus sonchifolius, distantly related to Jerusalem artichokes and carrying with it a host of intriguing culinary possibilities.

What is it?

Yacon tubers form underground beneath a robust, leafy plant, slightly reminiscent when dug of large baking potatoes, but that is where the similarity ends.  Yacon, meaning ‘water root’ in the Inca language, has flesh that is juicy, slightly sweet and yielding, with a flavour reminiscent of pears, or melons, with a hint of celery.  In fact in its home country, this beguiling tuber is used in fruit salads as well as vegetable dishes.

A most exciting feature of Yacon is the super sweet syrup that can be extracted from it, containing an indigestible sugar, inulin.  In effect the delicious toffee-tasting syrup is virtually calorie free, does not raise blood sugar, and so both tubers and sweet syrup are suitable for diabetics.  The inulin in yacon syrup also has great benefits for the bacteria in the gut where it is said to aid digestion and boost the immune system.  These health benefits have lead to yacon becoming a major crop, especially in the US where most of the syrup extraction takes place.

Growing Yacon

Yacon is a tender perennial plant, therefore with a little TLC, once you have your first plant, it should be with you forever; in fact its cultivation and care are very much like dahlias, so if you grow dahlias, yacon will be a cinch!  It is rarely troubled by any pests or diseases, easy and willing to grow, but does however need a long growing season, the tubers bulking up in the late autumn, to be dug in mild years just before Christmas, in advance of any penetrating ground frost.

To start off, either buy rooted cuttings in the spring or get a division from someone already growing yacon.  I usually treat my stored crowns like dahlias, starting them off in the greenhouse until shoots appear.  At that point I divide into individual plants and pot up, before growing them on for planting out in May in a sheltered sunny spot, when all danger of frost has passed.

Yacon does appreciate a rich, fertile growing medium with plenty of well rotted manure and compost, deeply incorporated into the soil.  Cultivating the soil to a good depth before planting greatly helps the process of lifting the crop in the autumn, otherwise the main tubers can break off and stubbornly remain in the ground.

Once planted out, a lush and leafy plant will quickly develop to a height of up to 2 metres, with small orange yellow flowers in the late summer.  If things are going to plan, the burgeoning tubers will start to raise the soil circling the crown of the plant around September / October time

Harvesting and Storing Yacon

Leaving harvesting as late as possible will give the most cropping potential.  When the moment arrives, usually when the top growth has been blackened off by the first air frost, cut back the remaining stems to about 10 cm and dig up the crown consisting of the bulky storage tubers (the crop), plus small propagation roots, or ‘buds’ growing just under the surface.  The crowns for next year’s plants are stored much like dahlias for the winter in a cool but frost-free place where they won’t dry out.




The big tubers, carefully snapped from the crown, are crunchy, sweet and refreshing immediately — after washing and peeling can be eaten just like a carrot — but they do have the potential to become sweeter if left out in the sun for a few days.  Only undamaged tubers can be stored for several months in paper or hessian sacks, much like potatoes, in a frost-free garage or shed.  Any damaged tubers should be used immediately or made into syrup.




Yacon in the Kitchen

Crunchy yacon is a delicious and different addition to savoury salads — try substituting the apple in Waldrof salad with diced yacon, or combine grated carrots, yacon ‘sticks’ and sliced celery with a grain mustard vinaigrette — in fact it absorbs dressings and sauces of all kinds very readily, making it a tasty vehicle for other flavours. In the Peruvian tradition of ‘salpicon’ (fruit salad), versatile yacon can also make a delightful fruit dessert when chopped and added to your choice of pineapple, melon, papaya or mango, dressed with fresh orange juice. If used raw, the flesh of yacon will discolour, much like an apple, so after peeling and preparing, sprinkle immediately with a little dilute lemon juice, or dressing, to preserve its attractive white colour.  Alternatively, for a hot dish, yacon can be roasted with other root vegetables tossed with olive oil, balsamic vinegar and herbs, or even just simply steamed.

Sweet Treat

Once you have grown enough yacon to have some spare you can think about extracting the sweet liquid using a food processor — about 12 kgs makes a litre of the precious syrup.  Simply wash and peel the tubers in batches then whizz them up thoroughly; place in a large pan and simmer down gently at about 103 C until a delicious dark brown syrup is formed.  This sweet liquid is wonderful on porridge, or has a great affinity with cocoa when making ‘guilt-free’ chocolate treats!


Phillippa Lambert

Phillippa Lambert is a landscape designer based on the Isle of Wight at a unique site in the Undercliff of the Island — a favoured microclimate sheltered by enormous south facing cliffs. In 2002 Phillippa and Stephen Lambert came across the ‘lost’ gardens of a Victorian mansion dating back to the 1820s, managed to acquire part of the site, including the walled garden and ornamental lake, and have since worked on their restoration. The result is not an ‘expert’ garden and does not try for technical perfection in any sense. ‘Make do and mend’ is the keynote — most plants being raised from seed or cuttings— and self-sufficiency is the motivation for all the growing in the walled garden. In essence, this site goes back to the philosophy of ancient gardens in sustaining the body as well as the soul. Read more at Lakehouse Design.

Yacón – makes sugar-free sweetener!

Yacón (Smallanthus sonchifolius) aka Peruvian ground apple, Bolivian sunroot

Yacon - makes sugar-free sweetener!

Yacon – makes sugar-free sweetener!

Sweet-tasting tuber makes ‘no-sugar’ syrup suitable for diabetics
Here’s an interesting tuber with the texture of water chestnuts and a sweet taste of pear with a hint of watermelon! Yacón is deliciously juicy, especially when freshly lifted and eaten raw – the word ‘yacón’ apparently means ‘water root’ in the Inca language and this turns out to be a very apt description. An exciting feature of this tuber which looks quite like a sweet potato, is that the liquid content from the tubers can be extracted using a juicer (or food processor – see Culinary Uses) and made into a super sweet syrup which can be used as a substitute for sugar, much like honey or maple syrup. And the best thing about the syrup, is that it’s virtually calorie-free! Yacón contains an indigestible sugar called inulin which means that yacón – the tubers AND the sweetening syrup – are suitable for diabetics.

How to make ‘sugar-free’ yacón syrup
Wash tubers thoroughly and whizz them in a food processor to make a pulp. Then boil the pulp in a large pan, using a cooking thermometer to keep the temperature at approximately 103°C, to form a dark brown syrup. Just four plants should provide the 12 kgs of tubers required to produce 1 litre of syrup.

Culinary uses of Yacón
Fresh tubers can just be washed – no need to peel them if they are just out of the ground – and sliced to eat raw as a snack, in salads or added to stir fries. It should be noted that the flesh will tend to discolour – like apples and potatoes – so sprinkling with a little lemon juice (or apple juice) will slow this process down. When using yacón in salads, it’s best to toss it in lemon juice (or in lemon juice diluted with water) and add it just before dressing and serving.

Don’t throw away the foliage from your yacón! A few fresh leaves from each plant can be cut during the summer and autumn, tied together and left to dry naturally in the kitchen or airing cupboard. Once dry, crumble them into boiling water to make a delicious ‘green tea’. Crumbled leaves will keep fresh for many months in an airtight container.

Yacón will absorb sauces, dressings and condiments so it can be used as a delicious and different ingredient in a variety of sweet and savoury salads. Try it with grated carrots and a grainy mustard vinaigrette as a colourful salad. Or chopped and added to a colourful fruit salad of pineapple, mango and pomegranate. Yacón can also be roasted along with other root vegetables, tossed in olive oil, sprinkled with sprigs of rosemary or simply steamed. The possibilities are endless.

Growing Yacón
Yacón is easy to grow in most soils, although deeper soils will provide a heavier yield of larger tubers. Plants will greatly appreciate the addition of compost and/or well-rotted manure each autumn. The height of the plants makes them ideal companion plants for spinach, French beans, courgettes and radish plants to utilise space in between plants and to provide dappled shade.

Planting Yacón
Grow yacón from ‘buds’ (also known as ‘caudices’) which should be potted up individually from February to early April in moist compost with the growing point upwards. Keep at about 18°C until shoots appear. Plant them out when the risk of frost has passed and once plants are approx. 7-10cm tall to ensure they establish more reliably. Position the plants in a sheltered, sunny spot, at the same time as you would plant out your courgettes. Plants are tall – up to 6ft (180cm) – so allow approx. 30in x 30in (75cm x 75cm) for optimum yields. Small flowers are produced in the summer and tubers are formed in the autumn. Frosts will tend to tinge the foliage, but a heavy frost will usually wither or blacken the leaves and it is then time to lift the tubers, usually during November.

Yacon - makes sugar-free sweetener!

Yacon – just harvested

Harvesting Yacón
Using a long fork, carefully lift the tubers as they tend to bury quite deeply in the soil, and will form a clump similar to a dahlia. Carefully break off the tubers. Any damaged tubers should be used promptly or made into syrup as they will rot in storage. Only undamaged tubers will store.

Crop yields
An average plant will yield 3.5-4 kgs of tubers.

Tubers store extremely well in paper or hessian sacks in a cool dry place in the shed or garage, but they need to be kept frost free. They often sweeten over time. Keep a couple of yacón tubers in the fruit bowl where they will ‘warm up’ and sweeten further before use.

Stored tubers will form a thicker skin, which turns a darker brown colour and will need peeling, as it becomes more bitter over time.

Yacon buds are available on the Thompson & Morgan website. Click here for more details.

Recipe suggestions from Mark Diacono at guardian.co.uk

Rebecca Tute

Rebecca works in the Marketing department as part of the busy web team, focusing on updating the UK news and blog pages and Thompson & Morgan’s international website. Rebecca enjoys gardening and learning about flowers and growing vegetables with her young daughter.

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