Back to my roots (and tubers)

One of this year’s experiments in the allotment has been to try to get more starchy roots, tubers and bulbs into the forest garden. I haven’t had any straightforward, unmixed successes, but definitely some interesting leads that I want to follow up.

One fruitful (rootful?) source of edible roots is the Apiaceae or carrot family, home to the carrot and parsnip amongst familiar roots, as well as a large number of the plants that we use as herbs and spices (cumin, celery leaf, coriander, parsley, fennel, dill…). In particular, I was interested to try the native members of this family that have a culinary reputation: sweet cicely (Myrrhis odorata) and native hogweed (Heracleum sphondylium). Both have other edible parts (with some care in preparation required for the hogweed) but that’s a topic for another post. This time I wanted to get to the root of the matter.

I have tried sweet cicely root before. Like the rest of the plant, it has a strong aniseed taste, although the flavour moderates with cooking. Even so, it is a root to use sparingly in dishes with milder ingredients rather than to tuck into a plateful of. Mature sweet cicely roots are truly massive – and so deep that they are next to impossible to dig out whole. Unfortunately they are also not very nice: I only find the first year’s roots palatable, so I think that the answer is to have a few favoured plants as perennials for shoots, leaves and seeds and grow the roots as an annual crop.

I sowed a few rows in a couple of different sites with different seed sources, intending to select for the largest and straightest roots. The results were interesting. Site one was in open vegetable beds. The roots were a decent size but almost all quite heavily branched. Site two was quite shaded and yielded smaller but much straighter roots. I’ll have to do some experiments to find out whether this was genetic or due to the shade. Anyway, super-cicely is not on the horizon quite yet, but I’ll keep working on it.

sweet cicely roots

sweet cicely roots

The situation with hogweed is much simpler to report. The boiled roots were revolting. Yuk. I think I’ll be leaving them to the hogs from now on – although it does occur to me that I didn’t get to try first-year roots…

Other carrot-family roots include Hamburg parsley, which I’ll write about soon, and skirret (Sium sisarum), a perennial which bears a multitude of sweet, pleasant-tasting roots. Harvesting it involves digging it up, taking off some of the roots and putting the rest back in the ground. Turnip-rooted chervil (Chaerophyllum bulbosum) is a biennial with very pleasant-tasting but rather small roots. There is some evidence that strains with larger roots existed in the past so I’ve been growing the biggest of mine on for seed.


Another two candidates were South American crops that I have tried before years ago and which I decided to have another go at: yacon and oca. Oca (Oxalis tuberosa) is a tuber-producing relative of wood-sorrel, so the tubers have that lemony oxalic acid taste when they are fresh, but fortunately if you leave them in the light for a while it goes away. The big difficulty with growing oca at this latitude is that they only start to tuberise at around the autumnal equinox, by which time the frosts might be only a few weeks away. This year there were no hard frosts until November and I decided to try a little experiment. The plants had grown luxuriantly and I felt that they still had a lot to put into tuberisation if they weren’t completely killed by the frosts. I dug up one plant, covered two in horticultural fleece and buried a fourth under a thick layer of leaves. A couple of days ago I dug up the protected plants to compare yields. They were:

325g first plant
400g each for fleece-covered plants
550g mulch-covered plant

I imagine that a statistician would tsk at the size of my trial, but the results do suggest that covering the plants was worthwhile. The leaf mulch was more effective at insulating the tops than the fleece as well as being cheaper. Overall though, the yields are still rather disappointing for the space taken up. I don’t think that oca will really fulfil its promise in Scotland until someone finds a strain that starts to tuberise immediately. It isn’t too much to hope for as potato suffered the same problem originally.

Oca tubers

Oca tubers

Yacon (Smallanthus sonchifolius) is also frost-sensitive but had managed to put on a more impressive set of tubers than the oca by the time the frost hit. Like the related dahlia (also edible but not very nice), yacon crowns have to be brought inside to overwinter. It has two kinds of tuber: vegetative ones which will grown the next year’s plants and storage tubers which you can pick off and eat. The great drawback of yacon is that, like so many otherwise-promising plants in the daisy family (Jerusalem artichoke/sunroot, chicory, dahlia, elecampane, scorzonera), its roots are packed full of inulin, a sugar which can’t be digested by humans but which our gut microbes happily use, creating rather a lot of gas in the process… The culinary virtue of yacon tubers is that they keep their crunch even when cooked, so a little bit in a meal is great for adding texture, but I wouldn’t want to try to live on them.

yacon tubers

yacon tubers

The pea family (Fabaceae) is better known for its seeds than its roots, but there is a small number of tuberous species and one fascinating plant called talet (Amphicarpaea bracteata) that has adapted its seeds to work as tubers. This year I tried growing aardaker (Lathyrus tuberosus, also known as the Fyfield pea or Dutch mice: the Dutch name means earth-acorn) and cairmeal (Lathyrus linifolius, also known as bitter vetch or heath pea: the Gaelic name is pronounced like Carmel).

The aardaker gave a small crop of inch-long, tapering tubers that did indeed put me in mind of both mice and acorns. I would rather grow them on than lose any of them by eating them, but everything I have read about them suggests that they are delicious. The yield wasn’t exactly large, but it was produced in a very small space and, like all the peas, they have the added virtue of fixing nitrogen from the atmosphere, so I definitely think that this is one to keep an eye on.

Lathyrus tuberosus

Lathyrus tuberosus

By contrast, the cairmeal tubers were tiny. I couldn’t even take a photo that showed them properly. I won’t give up on it but might just abandon it for a couple of years and see how it gets on. There are advantages to cairmeal that make me want to keep trying: it is shade tolerant and has a long history of edible use in the Highlands.

Silverweed (Argentina anserina) is another plant that is reputed to have been used in the Highlands but has a bit of a problem in the yield department. I’ve had it in my lawn for years but decided long ago that its roots weren’t worth the effort of digging them up.

This year, I thought it would be interesting to take a closer look at the growth habit of the plant and transferred a few to pots of compost. They are strongly runnering so it can be very difficult to dig up a whole plant from the ground. In the autumn I shook off the compost and got a great view of the roots – with their swollen sections often at the end of the root but sometimes with the root carrying on beyond them. On the plus side, the roots taste great. I’m going to keep growing them in pots in order to (a) stop them invading the rest of my garden and (b) see if I can isolate individual strains and compare them.



Finally, some negative results. Two plants that I grow for their edible flowers, king’s spear (Ashphodeline lutea) and day lily (Hemerocalis lutea) are said to also have edible roots so in the autumn I dug up a few and tried them. Neither seemed worth it. The burdock (Arctium lappa) that I sowed produced next to nothing, as it usually does. I don’t quite understand this as burdock grows well in the wild here. I consoled myself with the thought that since they are in the daisy family they probably aren’t that much good anyway [UPDATE: I was wrong. See here]. My hopniss (Apios americana), another member of the pea family, did what it always does: it used all the resources in the one tuber that I planted to produce a total of one solitary tuber at the end of the year. I’m beginning to think that I could achieve the same result by pickling it rather than by planting it. It was a similar situation with the pleurisy root (Asclepias tuberosa). I’m experimenting with a few plants in this genus but mostly I think the climate is just a little too cold for them here. My attempt to grow Chinese artichoke (Stachys affinis) took rather a blow when the supplier sent me what turned out to be the related wild flower betony (Stachys officinalis) instead. Finally, my rampion (Campanula rapunculus), which is said to have long, fleshy, white roots, produced nothing but fibrous roots. From talking to others, this seems to be a common problem: has anyone out there ever grown rampion successfully?

rampion - where's my roots?

rampion – where’s my roots?

Other rooty posts: Chufa/tigernut; Wasabi, horseradish and friends; Self-seeded parsnips; Growing pignuts; Dog’s tooth violet
Next installment: Back to my roots (and tubers) – 2016

35 thoughts on “Back to my roots (and tubers)

  1. Anni Kelsey

    As ever a really interesting and informative post. I have been planning to try the roots of my sweet cicely but as they are old plants I shan’t bother!
    I have tried something similar with oca – have buried some plants with mulch, taken one indoors to unseated conservatory in a pot – have yet to harvest, but outdoor plants were making new tubers near surface last week so I left them alone, am hoping there are some bigger ones down below! Will post results when I have them.

  2. Tracey Lloyd

    Great post, Alan. Oca is something another allotment down here tried, and it does ok some years, but was disappointing this year – in fact from the weights you posted, it looks as if yours did better, so I will pass on the mulching tip. Have you tried scorzonera? Ours have been in for 2 years, and the roots are still not much to write home about size wise so I’m wondering if we are missing a trick. I think we’ll have to try the dutch mice – look and sound v. good.

    1. Alan Carter Post author

      Hi Tracey. I’m not a big fan of scorzonera. Small roots in the first year; tough, tasteless ones when they get bigger – and packed full of the dreaded inulin. Dutch mice have to be worth trying for the name alone 🙂

    1. Alan Carter Post author

      I must admit I’m coming round to the idea of silverweed having potential, despite my scepticism when you suggested it earlier in the year. The yield I got this year wasn’t much, but for a scrap of plant transplanted mid-season it really wasn’t bad either. Then there’s that report of huge yields in the Highlands. Since that clearly didn’t come from digging up wild roots, I’m going to work on the assumption that (if true at all) it was from a lazy bed system and that the plant is able to respond to growing in a very fertile medium.

  3. Kate Godfrey

    Thanks for the post, as usual, fascinating! Disappointing about the day lilies, I was going to have a go at them this year. Well, I will anyway, for other reasons, but won’t be counting on the edible roots, although who knows what might happen in tropical Perthshire? Kate

  4. Rhizowen

    It certainly grows well in nutrient rich soils if the estuarine root gardens of the Pacific North West are anything to go by. I reckon a lazy bed heavily fertilised with seaweed might do quite well. If you need Chinese artichoke, let me know – I’ve probably got a few tubers knocking about.

  5. Carole Egner

    I was up at Findhorn in June last year and they were growing Oca in one of their gardens – perhaps it’s worth asking what variety and if their yields were lower than usual last year. I, and some other friends, found we had a lot of root veg giving huge top growth but not much underneath (eg potato, parsnips, carrots).
    As for Jerusalem Artichokes, my Fife Diet calendar tells me that if you cook/eat them with Lovage it reduces the digestive issues – this is on my “must do” list to try as we’ve a garden full of them and my husband is refusing to eat them on grounds of greenhouse gas emissions!

  6. Margaret Lear

    Hi Alan, Just read this one as am wondering when exactly to lift and steal bits off my Skirret – it has been in the ground about 15 months and I haven’t tried it yet! As it doesn’t seem to sell that well for some reason I suppose I can always replace it if I wreck it. Any thoughts welcome….
    On another note have just been given some Allium cepa Perutile and liking the sound of that from your earlier blog. The Daubentons Kale you gave me is famously productive and has multuplied many times – somewhere I saw it spelled Dorbentons and changed all my labels – which is correct please!? all the best Margaret

    1. Alan Carter Post author

      Hi Margaret. Skirret is lifted any time in the autumn or winter after there has been a frost and the foliage has died down. Glad to hear the Daubenton’s is doing well. It’s named after the French naturalist Jean-Louis-Marie Daubenton so ‘Daubenton’s kale’ is the correct spelling. There are lots of variations floating around, including some people sticking in an apostrophe to make it sound more French – D’Aubenton – but since French sites never use this spelling it seems unlikely to be right. I ordered some ‘ewiger kohl’ (everlasting cabbage) from the Agroforestry Research Trust this year and it seems to be absolutely identical to the Daubenton’s. Cheers. Alan

  7. Ken Wilkinson

    Hi Alan, I’ve just had a quick read through. Lots of good stuff to follow up on.
    A few comments which may be helpful, but I’m on the Isle of Wight, so milder here.
    Skirret is delicious, but may need 2 or 3 years to get to a decent size. Don’t sow them too close, as I did, or they end up in a huge tangle, and are smaller.
    Oca were left in the ground till late in the season, but mainly eaten by mice when dug. Nice cooked, but raw they are a bit lemony, but also have a taste of raw potatoes which I’m not keen on.
    Chinese artichokes are nice in salads, but mine are very small and fiddly to clean.
    Jerusalem artichokes are one of my favourites. Very easy to grow, useful windbreak too. Nice raw in salads, also sliced and fried as well as the usual soup and stew.
    Yacon is great too. I love it in salads in the winter. It stores well for months, and gets sweeter with storage.
    My lovage dies down now, and comes up in the spring, so the opposite season to the artichokes. Maybe it could be frozen or dried, or perhaps the seeds used.
    I let parsnips self-seed, and also broadcast them around the place. They sometimes grow huge when on their own like this rather than me sowing them too closely in a row. They seem to look after themselves, and are good in stews etc. Nice fried too.
    Scorzonera always seems very small, but nice flavour. How big are the roots supposed to be?
    I intend to try other tubers and roots, but these are the main ones I have so far.
    All the best

    1. Alan Carter Post author

      Hi Ken. Thanks for all the comments. I find that swirling Chinese artichokes round in a bucket wth a bit of water and some sandy soil cleans them quite nicely. Life is too short to clean them individually! Scorzonera roots are long and thin: maybe 15 mm diameter and 300mm length for a good root. They are perennial and will grow massive if left in the ground, but not, to my taste, very nice. I prefer both salsify and burdock so I don’t grow scorzonera much. I agree that skirret is delicious: I harvested some a couple of weeks ago and have been enjoying them very much.

  8. Randy

    Glad I came across this thread. Lots of good suggestions. One root plant that needs no form of care is radishes. Of the tubers mentioned which would grow the best in shady areas along a slope with no maintenance?

    1. Alan Carter Post author

      If your climate is similar to mine then hogweed and sweet cicely would do well in the situation you describe, but in both cases they are really more useful for their shoots than for their roots. The best shade-bearing root crop I have come across so far is Erythronium ‘Pagoda’ or dog’s tooth violet, which has its own post.

      1. Randy

        The dog’s tooth violet sounds interesting. May try. Our area is zone 8b with alkaline soil in the Texas hill country. Any plants would need to be able to take our hot summers.

  9. Rain Adkins

    About burdock root: Most of the vegetable-use strains need nearly full sun and require that the soil be very deeply worked. They produce big yields of fantastically tasty roots, but the best way to plant them is in barrels (not halves, whole ones) or tall raised beds, and not in the woods.
    Message me if you want a recipe for a really good burdock-and-mushroom gravy or stew. Meanwhile, if you have a yen for burdock root, phjone local Asian groceries and ask for it by the Japanese name, gobo (to rhyme with “Yoko”, not “slobbo”).

  10. Alan Carter Post author

    Since I wrote this post I’ve been persisting with burdock and have become quite fond of it, especially as kinpira gobo. I find that getting it to germinate is the hardest part and my usual solution to this is to produce my own seeds so I let a few plants run to seed this year. They reached 3m high and are covered in burrs that do their best to enlist me as a seed vector every time I go by, so I think it’s been successful!

  11. joachim

    Interesting article, thank you! My experiences with Yacon are very good, with oca good (like the taste less than yacon, but good quantity too), and my experience with Stachys affinis and Sium sisarum are no good at all. Mice/voles ate EVERYTHING. Not one little tuber – or plant – left. Dammit. The Sium might selfseed, stachys didn’t flower so that is just gone.

      1. joachim

        Both where in the ground. Althaea officinalis was also eaten mostly. I’ll have to get my jerusalem artichokes out of the ground before they disappear too. Pretty frustrating: planting a perennial garden, and to end up having to replant every year…. I believe the fault lies entirely in the industrial agricultural system around here. Big fields without trees or hedges between them where predators birds and mamals can nest. My trees are too small to put owl boxes…

        1. Joachim

          NO NO NOOOOO. Lunaria annua is mostly gone too. Apart from four big plants, the complete roots of most plants are eaten off. I’ll get back to turning the soil and sowing annuals if this continues… Or i’ll get back to a lawn or something.

          1. Alan Carter Post author

            Oh dear. That does sound rather extreme. You seem to have super-mice. I had a similar experience with broad beans this year. I didn’t manage to get out to the plot where I was growing them until quite late and when I got there there were neat holes all along the pods and all the seeds gone – every one. They were several genetic lines that I’ve been selecting on for some years now so it wasn’t just a loss of the beans as food.

          2. Joachim

            ah thats too bad… What does apparantly help to keep things a bit safer (at least for root crops) are open spaces and interplantings with leek. (seeds, standard edible from the food store, or allium Molly for some more flowers) We finally have some winter here – hope some mice/voles freeze to death. Ik recently saw what i thought was a marten or polecat coming from under our car. Might be that i create some living space for the animal by making a hollow in our stacked wood. If we would have one in the garden, it’s a mice predator with even less work than a cat 🙂 Ofcourse there is a risk for car cables, neighbourhood chickens and eggs, and it might also just decide to get under the roof of our house instead of in the wood. I’ll no longer take hostage of your roots story and will not kidknap it into vole territory anymore 🙂 Greetings!

  12. Ken Wilkinson

    Mice can be a big problem. I had the same thing with broad beans. Are cats an answer? No use for plots where you don’t live though.
    I’ve found wind-up multi-catch traps pretty good, and also there are plans for traps around. Anyone have useful experience of any? Single-catch traps are less use, I think.
    Poison may work, but I don’t like the idea.

    1. Alan Carter Post author

      I think with the broad beans it is simply a case of harvesting them in time. I don’t go out to the plot in question often enough for traps as I wouldn’t be able to check them regularly enough.

      1. Ken Wilkinson

        You may be luckier than me, but I have found once they have found them they take them before they are full size. It seemed to take them a few years to find them. Last year I grew some for the first time on another plot which has mice, but not touched.

    1. Alan Carter Post author

      Hi Anders. My efforts at most things have been a bit set back these last 2 growing seasons by suffering a slipped disc, but I still have the seed source with the straighter roots. I’ve also been bulking up my supplies of a strain from Denmark which is hairless. I’ll try sowing some of its seed this winter to check out the roots.

  13. C

    I just dug up a bed of rampion. I had given up on it since the few times I dug up a plant I saw only fibrous roots. I left the bed abandoned for a few years and let them spread and when I went to eradicate them to plant something else, lo and behold there were tons of fat white roots! Perhaps they need a few years to get big?

    1. Alan Carter Post author

      Interesting! Do you know what species that was, as the common name rampion gets applied to a few different species? Did the bed consist of the same plants the whole time or did it look like they were reseeding themselves every year? Did you try eating them? And do you have any spares? 🙂

  14. Johan Barth

    Thank you for this post. Living in Holland, I plant and harvest lots of yacon. It’s one of my favorites. I have no problems digesting it.
    – When the plant dies, I harvest the tubers and store them in my cellar in buckets with holes in the bottom. I cover them with a layer of dry leaves.
    – This way they store for months.
    – You need to wait some weeks before eating them. During storage, they become sweeter.
    – I use them sliced on bread, with cheese, Mediterranean herbs, or honey. My daughter eats them with peanut butter.
    – In receipts, I replace sweet pepper (paprika) with yacon. I use 50-100 gr. p.p., cut in small pieces. We eat them with rice, mi, etc.
    So we eat many kilograms of yacon every year. And we all love it.
    Yacon needs fertile soil. My best place is where the compost heap was located last year. It grows up to more than 1,5 m. In hot summers it sometimes starts flowering. I plant yacon at 90×150 cm. Short living annuals can be sown between the plants, to be harvested before yacon grows tall.
    Maybe this comment may help others to appreciate yacon.


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