A very mild end to 2014 in Aberdeen meant that a lot of my root crops didn’t get harvested until the end of December and I am still digging some up now.

The late frosts were ideal for the oca, which only starts to tuberise around October and therefore had a good long season. In a bad year here frosts can cut it down before it produces any tubers at all. As well as the ones I planted, I had a crop of volunteer oca coming up where I had them last year. Interestingly, they had the same yield as the planted, manured crop and bigger, better tubers. I suspect that this is down to the wider spacing and resulting larger individual plants. They were also less chewed-on by beasties in the soil, presumably due to the lack of compost. I’ll try to recreate these conditions with my deliberate crop this year. One surprise when I dug up my oca was that one tuber on one of the plants was almost white, compared to the pink/orange colour of the rest. I’m told that such colour sports are quite common in oca, and look forward to propagating my very own strain!

Roots, tubers and swollen stems form a pretty large part of my diet in winter. I counted twelve in last night’s stew, some from store, but mostly just dug up: turnip, sweet cicely, potato, oca, yacon, carrot, parsnip, salsify, Hamburg parsley, udo, Chinese artichoke and skirret. Such a variety gives a wonderful flavour even with the simplest of cooking methods. Two of the above perhaps count more as spices than as main ingredients: the sweet cicely and the udo. Sweet cicely root has a strong aniseed taste which is overpowering raw or in bulk, but adds a great flavour sliced thinly and sparingly into any dish. I dug up a mature sweet cicely of maybe four or five years’ growth this autumn, being as careful as I could not to break the root. It finally snapped off at about one inch in diameter. The part I dug out was over a metre long. It would have been interesting to have excavated the last section to find the total length, but I had reached the limit of my spade! Perhaps not surprisingly, this one root has met all my sweet cicely needs so far this winter. It has stored extremely well simply kept in a cool place (being far too large for my fridge).

Udo (Aralia cordata) root is similarly best used sparingly but at least it is easier to dig up. It has a similar taste to the spring stems, with some slightly harsher notes mixed in. The real gourmet food available from udo at this time of year is the underground stems that it puts out as runners to spread itself. Cooked briefly they have a melting texture and a taste very similar to the spring shoots.

There were a few other rooty experiments during 2014. Burdock (Arctium lappa) root cooked as kinpira gobo was utterly delicious, but I have had to restrain myself as I would like to grow most of my roots on for seed. I often have trouble getting bought burdock seed to germinate and my usual solution for that is to produce seed myself so that I know it is fresh. By contrast fennel roots were a disappointment. Fennel (Foeniculum vulgaris) self-seeds itself freely around my allotment and its roots are edible, so I had high hopes, but they turned out to be extremely bland and boring, with none of the flavour of the leaves or seeds. One breeding task I set myself this year is to see if I can get my very hardy and vigorous herb fennel to cross with the bulb-forming Florence fennel. They are just different selections of the same species so how hard can it be?

Skirret – Sium sisarumAnother root with lots of potential is skirret (Sium sisarum), another carrot relative. Instead of the traditional single root it produces a massive cluster. This makes peeling a job only for the seriously dedicated, so I always use them with the skins on, which fortunately is fine. They have a deliciously sweet, carroty taste and a nice floury texture after just a few minutes cooking. Cooked longer they will disintegrate entirely, which can be useful for flavouring soups or stews. A cluster like the one above will grow from a small division if it is given a rich, moist soil. I clearly didn’t give it quite enough moisture this year as my roots had a thin, woody core, which they develop in dry soil. This can be worked round by using the roots sliced thinly, but this year I have dug them a sunken bed next to the water butt and dug in plenty of leaf mould, as I feel that this is a crop really worth getting right.

Chinese artichokes (Stachys affinis) also did well. For anyone who hasn’t tried these before, they have a mild flavour and a nice crunch and look almost exactly like big, fat, white grubs, to the extent that I managed to kid my flatmate on for a good while that that was what was in the evening’s stew. I also tried rough bugleweed (Lycopus asper), which is similar to Chinese artichoke in many ways, but to my mind inferior in both taste and texture.

Two more tubers, both in the bean family: regular readers might remember my struggling hopniss (Apios americana) tuber, which every year manages to scrape together enough resources to yield exactly one tuber at the end of the season. This year’s warm conditions allowed it to produce an unprecedented six tubers. Needless to say, these are far too precious to consider eating: with such an abundance I’ll be able to try a few more ways of growing this fascinating plant before I finally admit that it is too cold for it here. That point may come a little sooner with talet (Amphicarpaea bracteata). Strictly speaking talet doesn’t produce tubers but beans growing on underground stems which serve the same function. Since growing underground poses certain challenges to fertilisation, the beans produced in this way are asexually produced and, in good conditions, the plants also bear an above-ground crop of seeds in the usual way. Unfortunately, in my case I ended up with vastly less reproductive material than I started with. I began with a good source of seeds, sourced from the northern end of talet’s range in Nova Scotia, and a handful of tuber-beans. Although I felt rather like Jack planting these, magic beanstalks did not result. In a wide range of planting sites, including a pot in my balcony, my allotment and another site further inland which experiences slightly hotter summer conditions, the plants grew very weakly and at the end of the season careful digging managed to produce only two underground beans. I’ll do what I can with these next year, but more in hope than anticipation.

Moving above ground, a few hardy plants are still giving me fresh veg straight from the garden despite the sub-zero temperatures. Daubenton’s (perennial) and Pentland brig (biennial) kale are still performing well. Nine-star perennial broccoli also produces tender and sweet leaves that are excellent as a winter kale, despite being a cauliflower than thinks it’s a broccoli! Leeks (Allium ampeloprasum var. porrum) are for me the undisputed king of the Scottish winter garden. I only grow winter varieties such as Bandit and Musselburgh, the latter being a traditional variety that has never been beaten. There are so many other alliums available in the perennial garden for the rest of the year that there is hardly any need for another, but in the depths of winter leeks really come into their own, laughing at freezing temperatures and even continuing to put on a little growth, with a flavour that for me beats even that of cultivated onion (Allium cepa). Garlic (Allium sativum), elephant garlic (Allium ampeloprasum var. ampeloprasum) and Babington leek (Allium ampeloprasum var. babingtonii) are all putting up shoots that could be cut and harvested, although apart from some garlicky-tasting leaves from the elephant garlic I mostly leave these for spring and summer harvest.

Having read Stephen Barstow’s book, I plan to do a lot more with indoor sprouting of seeds and forcing of roots for greens next winter. Since Stephen managed a salad with twenty different plants this week despite the 24-hour darkness of a Norwegian winter outside, he clearly knows what he is talking about! As an indication of what can be done, a salsify root left in the fridge while I was away over Christmas took matters into its own hands and produced a large head of succulent, white leaves. Finally, despite the sub-zero temperatures outside, one plant is already beginning to sprout. The leaves of alexanders (Smyrnium olusatrum), picked just as they emerge and slowly fried in butter, have a delicious taste that gives a promise of a new season to come.