The idea of a plant that produces an edible crop and doesn’t need to be sown or planted every year is very appealing. Of course it is not that weird an idea since potatoes are strictly a perennial crop, though we tend to buy new ‘seed’ every year. And yet perennial crops are not that common or popular (I am not including fruit in this definition).

I am always attracted to the unusual so I grow more ‘perennial veg’ than beetroot or peas. Well, that has been the case, but this year will be the tipping point because I have, reluctantly, ended my love affair with my four perennial vegetables. I have changed my ideas on peas simply because it is nice to graze in the garden so peas are making a comeback this year for that reason alone.

It was the late, great Geoff Amos, straight-spoken, old-fashioned gardener that he was, that memorably declared that Jerusalem artichokes were the only vegetable unfit for human consumption. I always try to see the good in things so it gives me no pleasure to say that Jerusalem artichokes give me wind. Batches of soup in the freezer is labelled just ‘fart soup’. And thawed with trepidation only on days I am not going out. I currently grow a variety called ‘Sugarball’ and I initially thought that it was going to be easier to digest than varieties in the past but it was not to be. I am really sad about that because I like the taste.

And this is a very easy crop to grow. It will thrive in any sunny spot and produces lots of tubers. They seem quite resistant to slugs and other soil pests – or perhaps they are ejected from the garden after eating them, like little balloons when you let go of them. But their fecindity is also an issue. You never get all the tubers out because they spread and go deep. The plants are tall and here they always ‘lodge’ in late summer, making it awkward to get past the beds. I really want to love them but I am getting close to resenting them. I will grow a few this year but I am not sure why.

I am glad to have Chinese artichokes (Crosnes) in the garden. Once again, I like these simply because I am awkward and they are unusual. Botanically Stachys affinis, this herbaceous relative of mint has dark green leaves, tiny purple flowers and spreads across the ground as quickly as mint. The good news is that it is hardy and it is easy to grow. It is grown for the slender, lumpy tubers that are creamy white and about 5cm long. But their size depends on the vigour of the clump. It is difficult to dig out all the tubers from the soil and if you expect to lift what you want and leave the rest in the ground to crop again you will only get small tubers. Mint is a traveller and grows best in fresh soil and Crosnes do too. (They are named after the French town of Crosne where they were first grown in Europe).

The tubers are crisp and crunchy and have a mild taste that is possibly nutty but I think has a distinct, aromatic hint of horehound, which is a close relative and not edible. It is versatile in the kitchen but needs only quick cooking or the small tubers cook to mush – just a few minutes steaming or frying is plenty. But the real pain is getting them from the plot to the plate! The tubers are small and incredibly fiddly to clean. And when you have to discard those that have slug holes it can be very dispiriting. I dig them, pick them over, hose them in the garden, pick them over again and then they get to the kitchen where I power wash them again and again before I pick them over, excising the bad bits and picking any remaining dirt from the grooves between the lumps in the tubers. Is it worth it? Absolutely not. The good news is that you don’t need to peel the tubers.

I have moved them this year though I can see that they are coming up again in the cleared area. But I am growing them in pots of multipurpose compost this year. I am hoping that, in fluffy, moist compost and well fed and watered, I will get better crops of larger tubers that will be easier to clean. I see that, in France, the tubers cost more than 20 euro a kilo, which seems like a bargain when you consider all the hassle to get a handful of edible ‘stuff’. On the positive side, bees like the flowers.

And so we come to Oca. It is easy to grow, has no major cultivation problems and has attractive, weed-smothering foliage. It is an oxalis, which may strike fear into the hearts of some, but it is not invasive. The edible bit (you can nibble the leaves if you need to) are the stem tubers which are formed just below the surface. The problem with this crop is that the tubers do not form until very late in the year, often after many of us have had the first frost of autumn, which kills the foliage. So you either have to cover the foliage in autumn with fleece, or grow it in pots you can move around, if you don’t live in a mild area. If you live by the coast and have sandy soil you may be laughing. But I am not. So I have grown it in a polytunnel and the crop is not really worth the effort. The tubers are surprisingly bland and a good alternative to potatoes. But at least they don’t get blight. But nor do cream cakes and I know which I would rather eat.

I will persevere and grow them in pots this year and see if I get a better crop. I want to love it.

Which brings us to yacon (Smallanthus). This is a relative of Jerusalem artichokes and has many of the same nutritional benefits (oligosaccharides that are prebiotic) but has a slightly different structure below ground. While J artichokes produce ‘stem tubers’ that are edible and have leaf scars along them and a growing tip, yacon produces growth tubers at the base of the stem, which are kept to replant the following year, and large, storage tubers below that we harvest and eat.

This is rather like the growth habit of dahlias. In recent years much has been made of the edibility of dahlias but I don’t like the smell of dahlias much so this doesn’t appeal to me. Yacon produces large, very crisp, crunchy roots. In warmer climes they can be quite sweet and almost pear-like but mine are a bit bland but with that ‘dahlia tang’. I wish they were nicer because they are good for stirfries, crop well and the plants are attractive and have nice yellow ‘sunflowers’. Of the four, this is the most practical. But it is not hardy and the ‘growing tubers’ need winter protection from frost.

The retrospective nature of this post is because this week has been wet and windy and the garden is a quagmire! And it looks like the rain is here to stay all week.

chinese artichokes, crosne, geoff amos, jerusalem artichokes, oca, yacon