This post (a catch up on my experiments with all things subterranean) is a little later than I expected. Many roots and tubers are not lifted until after the first hard frost. This can hit in October or even September in Aberdeen, but this year there was nothing significant until January, so many plants just kept on growing. The other factor is that I am still recovering from a slipped disc I suffered last spring, which means that I have to ration my effort in the garden and watch the heavy digging.
Now, however, the harvest is complete and the results (as well as the roots) are in.
Some plants have by now become staples of the forest garden and my winter diet, including oca, yacon, skirret, Chinese artichokes and TPS potatoes. The slipped disc meant that some of these had to cope with very late planting and considerable neglect over the year. In some cases that meant that I only just scraped through the season with my planting stock intact. Fortunately, however, roots and tubers are forgiving plants. They carry generous reserves that allow them to grow quickly and smother annual weeds, so some of them did quite respectably all the same. Roots that I allow to self-seed in the garden, such as parsnips and salsify, did so with little fuss.
These are exciting times for the breeding of many root crops. My oca and yacon both flowered, but far too late in the season for seed, so I think I’ll have to leave those projects to collaborations with a more southerly distribution, such as the Guild of Oca Breeders. Yacon was once thought to be sterile, but the Cultivariable seed company in Washington State has managed to make a range of crosses (I can highly recommend Cultivariable as a supplier of most of these plants). Yacon seems to be an obligate outcrosser – that is, it needs two or more varieties grown together to produce fertile seeds. Anyone with two varieties of yacon and enough sunshine can join in the fun.
I had more luck producing potato seeds. Potatoes also struggle to fruit in time here, but the fruits can be ripened up on the windowsill like tomatoes and will reliably produce viable seed this way. It helps that TPS (true potato seed) varieties can be stunningly blight resistant, meaning that they get the chance to keep on growing right up until the frosts. There’s more on why you might want to grow potatoes and many other things from diverse seed in my post here.
Another reason I find for producing my own seed is that a number of root crops can be quite difficult to grow from bought seed as they do not store well and can have tricky germination requirements. My usual way around this is to grow my own, giving super-fresh seed that I often sow in autumn rather than spring. I managed to do this with burdock (Arctium lappa) this year. My saved roots sprouted to nearly 3m high and produced an abundance of the spiky seed heads that were the inspiration for velcro. The only drawback was that they tried to recruit me as a seed vector any time I passed. Burdock seeds may get so lodged in the coat of an animal that they stay with it until it dies, giving the germinating seed exactly the rich, fertile conditions that it likes. I love my plants, but that’s where I draw the line! Seeds that I collected and sowed in autumn are already germinating despite the snow on the ground this week, so I am already looking forward to a summer of kinpira gobo.
A plant that I have similar problems in getting viable seed with is Hamburg parsley so I am trying the same approach this year, with several choice roots saved for seed production. Turnip rooted chervil (Chaerophyllum bulbosum) benefits heavily from this approach too – I’ll post more about this plant soon.
Going back to the Andean root crops, I had promising results with two more. One that I tried for the first time was ulluku (Ullucus tuberosus) – also known as papalisa, ulluco, milluku, chugua and ruba. Ulluku produces both edible leaves and tubers that taste remarkably like beetroot. It put up with severe neglect and still cropped reasonably well for me. Undoubtedly the most striking feature of ulluku is its looks: the tubers come in a dazzling array of buttercup yellows, rose pinks, lurid magenta and porcelain white. Digging them up is like unearthing semi-precious stones. On the downside, centuries of vegetative propagation have left many lines of ulluku virus-ridden and reluctant to produce seed. Yet again, Cultivariable is having spectacular results in coaxing this species back into reproductive life, so I think we can expect to hear much more about this species in the next few years, with cleaned up tubers and new varieties.
The other new South American is mauka (Mirabilis expansa). Mauka is described on Wikipedia as growing at “cold, windy altitudes” in the Andes, which sounds just ideal to me! My mauka seeds rather surprised me by germinating immediately when I put them in the fridge to stratify, so I now have six little mauka seedlings growing away, just waiting to experience the cold, windy altitudes of Scotland (i.e sea level).
I have spent a while gathering plants of silverweed (Argentina anserina) from different locations and planting them in large pots outside. The reason for this curious behaviour is that silverweed is a very strong spreader, so without control you will tend to have just one extensive clone in your garden. I’d like to get seeds of this plant in order to try breeding it, since it is delicious and locally well adapted, but has the drawbacks of thin, straggly roots and that agressive spreading habit. A non-runnering variety would be favourite! I wasn’t able to collect any seed last year, but the plants all look healthy and I hope for better results this year.
Finally, a hill of beans. The bean family (Fabaceae) contains a number of species with edible roots, including talet (Amphicarpaea bracteata), hopniss (Apios americana), aardaker (Lathyrus tuberosus) and cairmeal (Lathyrus linifolius montanus). With me, the Lathyrus species have been disappointing: my aardaker has almost died out, while the cairmeal is growing quite cheerfully without producing anything that could be seriously regarded as an edible root. Neither the talet nor the hopniss made it out of the greenhouse and into the ground this year. Both seemed quite happy with this arrangement: both flowered and the talet produced seed. On the other hand, the hopniss produced only one tuber per tuber and I couldn’t find any of the subterranean beans that are meant to be the main yield of talet. Both are now lying low and, I imagine, dreaming of better weather and better health on the part of their gardener for the year ahead. Me too.