August 2025

I was wandering around Waterstones bookshop on a visit to Cambridge last month when my eye fell on a copy of Martin Crawford’s book “How to Grow Perennial Vegetables” (2012). It was the words “low-maintenance” on the front cover which attracted my attention. Ever one to save effort where possible, I bought it. And developed my latest craze.

Perennial vegetables and fruits can be defined as edible plants that live for at least three years and can be harvested without killing the whole plant. Some plants are perennial in warm climates, but not in cooler ones, therefore do not count as perennials in Europe.  Many perennial vegetables we don’t usually hear of are an important part of diets around the world, for example the ulluco  (Ullucus tuberosus), a root crop apparently second in importance only to the potato in the Andes.

Perennials are said to contain more nutrients on average than annual vegetables, and to be better for the environment since you don’t have to disturb the soil so often, although you do have to get rid of weeds as soon as possible. Since they are usually allowed to flower, they are good for pollinating insects, which are currently under threat. Harvesting tends to extend over a longer period of the year, so they are useful during the traditional ‘hungry gap’ in spring, when you have used up your stored crops but the new ones are not yet producing anything. The root system of perennials is ready to start growing in early spring, so it makes the best use of a short growing season.

They do have some disadvantages, especially for large-scale commercial growers. They are harder to weed around by chemical or mechanized means. Crop yields are lower, since the vegetable has to use some of its energy keeping its root system going for next year, and they take longer to establish. And they are just as prone to diseases like club root as annuals, which is why I am regretfully not going to try any of the perennial cabbages, although they sound great (my main bed is infected with clubroot). The fact that they are not rotated like annual crops, but remain in the same bed for years can make this problem worse. 

The commonest perennial vegetables currently grown in Orkney are rhubarb and globe artichoke, and soft fruits like currants, gooseberries and berries. Most gardeners up here grow rhubarb, and if you don’t, there are often feral rhubarb plants available, like the ones at a beach near me. (It’s a pity that I can’t eat rhubarb any more myself).  I recently visited a garden on Hoy where they have planted asparagus. I have a sorrel plant which is fast becoming established and producing useful quantities of leaves. A local grocer was selling ramsons (wild garlic) in pots this spring, so I bought one.  

Watercress (Nasturtium officinale) is also worth trying. Apparently you do not need a fast-running stream to grow watercress; you can grow it in a container and keep the compost moist by standing it in a saucer full of water. The saucer needs to be emptied and the pot flushed through with clean water periodically to keep it fresh. That's also a good idea from the midge point of view as well. They breed in stagnant water and they don't need much encouragement up here.   You can grow watercress from seed, or you can do what I have done. Next time you buy a bunch, put some sprigs in a jar of water on the windowsill. Hopefully it will grow little roots in a week as mint does, and can then be planted out.   

The various blogs about perennial vegetables which have appeared in recent years also mention wild plants usually regarded as weeds. My garden, like everybody else’s, goes yellow with dandelions in early summer. I have no objection to eating dandelion leaves in salad or young nettle tops in soup. I can’t be bothered with Good King Henry, though. As a young archaeologist, I naturally tried a variety of wild greens such Good King Henry and Fat Hen and found them stringy and just tasting vaguely of greens, while ground elder I found had a positively objectionable tang.

Silverweed (Potentilla anserina) grows prolifically in Orkney and the thin roots were used as a famine food in the past.  The roots are small and spindly in the wild and it takes a lot of effort to collect enough for a meal (Milliken & Bridgewater 2013 pages 47-49).  However, F. Marian McNeill (2010, page 229) quotes Alexander Carmichael (Carmina Gadelica Vol. IV) as recording that before the introduction of potatoes, silverweed was cultivated in the Highlands and Islands and grew quite large. It was sometimes boiled, or sometimes the ground-up roots were made into porridge or bread.  She gives a recipe for Silverweed Bannock which is not a famine recipe. You are supposed to go over a ploughed field in spring to collect the long thin white roots, dry them and grind them up, and then make a bannock by mixing them with oat or barley meal, butter and warm milk and cooking them like a scone or an oatcake. It is said to taste nice but not as if it has much potential as a future staple crop.

What I am going to try next is skirret (Sium sisarum), known as crummock or crumag (Gaelic) in Scotland. I have bought two plants from a fascinating small firm in Devon. Skirret is a root crop with a sweet taste something between a carrot and a parsnip. Various European countries know it under the name of sugar root because of its sweetness.  It seems to be very popular at the moment and it does seem to have interesting possibilities. It doesn’t mind a cold climate and grows well in Britain and Northern Europe; it is resistant to disease, although it grows fibrous if it doesn’t get enough water.

 Skirret originated in China and was introduced to Britain by the Romans. It was cultivated thereafter for centuries. The 14^th  century English recipe collection known as the ‘Forme of Curye’ gives a recipe for fritters made of parsnips (‘pasternakes’), skirrets (the spelling varies wildly)and apples: these are dipped in batter made of flour, eggs, ale, saffron and salt and fried in oil or ‘grece’. They were served with almond milk. (I am going to try that one). Skirrets were a favourite in Tudor and Stuart times, and were planted in the royal kitchen gardens laid out by Queen Anne in 1702 at Hampton Court Palace. According to Geddes (1994, page 37), the recipe book of Katharine Bruce, Lady Saltoun, married to a late 17^th century Scottish laird, has a recipe for boiled chicken stuffed with parsley and surrounded by vegetables such as boiled artichoke hearts or skirrets in a sauce. Skirrets were being grown in Shetland gardens by the end of the 17^th century (Fenton (1978 page 421). But by the late 17^th century, potatoes were being grown in Britain in significant quantities. Potatoes are easier to peel, as skirret roots are long, thin and uneven, and they are easier to harvest industrially. Sugar was more widely available too, so the sweet taste was less important. The skirret gradually fell out of fashion.

Perennial vegetables are not totally labour-free. You still need to weed them, feed them, and keep them well-watered, especially if you are growing them in containers or a restricted space like a small raised bed. I seem to have spent most of my garden time this summer, which has been unusually dry in Orkney, pouring water onto my vegetables. My water butt has run dry twice. And I won't know until next summer whether my artichokes, skirrets and watercress are going to survive and produce an edible crop, whereas this year's potatoes have been great, in spite of the drought. We'll just have to see….

F. Marian McNeill 2010 “The Scots Kitchen. Its Traditions and Lore with Old-Time Recipes”

William Milliken & Sam Bridgewater  2013 “Flora Celtica. Plants and People in Scotland”

Alexander Fenton 1978 “The Northern Isles: Orkney and Shetland”

Olive M. Geddes  1994 “The Laird’s Kitchen. Three hundred Years of Food in Scotland”

2025 has been an extraordinary summer. I went south to the London area to visit friends and family, and I have never experienced such conditions since I was working in Greece and the Middle East fifty years ago. Temperatures were over 30 degrees C. Everywhere I went, green lawns were burnt to a crisp, and we had to carry water bottles, and stay indoors during the midday hours. The effects of global warming have become starkly clear. Orkney hasn’t been so badly affected, but we have still had long periods when temperatures were over 20 degrees C and our gardens needed a lot of watering. So am I going to start planting olives and lavender? I don’t think so. Because global warming may well affect the Gulf Stream, which is a major factor in the Scottish climate.

The Gulf Stream is a warm surface current which flows from the Gulf of Mexico, up the east coast of America, to the North Atlantic and Northwest Europe. The north-eastern extension of the Gulf Stream is known as the North Atlantic Current, the North Atlantic Drift or the North Atlantic Sea Movement. It is this part of the Gulf Stream which reaches Britain. The warmth it brings keeps temperatures in NW Europe higher than they would otherwise be at these latitudes.  It is the reason why palm trees will grow on the west coast of Scotland at places like Inverewe in Wester Ross, and why Orkney, at latitude 59 degrees north, has a cool mild climate rather than a cold one.

The density of the water is important as well as its warmth. This depends on its salinity as well as its temperature. When it reaches the Arctic, the water of the Gulf Stream has cooled and become saltier, so it sinks below the surface and flows south again as a cooler deep-water current. This circulation around the Atlantic is known as the Atlantic Meridional Overturning Circulation or AMOC. Global warming means that not only is the ocean warming up, but the Arctic and Greenland ice sheets are melting, releasing huge amounts of fresh water into the ocean and reducing the salinity of the northern Atlantic. The AMOC is already slowing down and eventually is likely to slow down significantly even if it does not stop entirely. If this happens, NW Europe, including the whole of Britain, may well become colder and stormier, although it is also argued that the effect of general global warming may to some extent compensate for this. There appear to be different estimates of how much colder and how soon this is likely to happen. But it could happen relatively quickly.

It has happened before. At the end of the last Ice Age, the planet was gradually warming up. But from around 12,500 until 11,500 years ago, i.e. a period of about 1,000 years, there was an abrupt return to very cold conditions in the Northern Hemisphere. The Southern Hemisphere grew warmer at the same time. Within a few decades the annual air temperatures in Europe dropped by 2-6 degrees centigrade, mainly in the winter. This cold period is known as the Younger Dryas, named after the flower ‘Dryas octopetala’ which flourishes in these conditions. Various causes have been suggested. These include a meteor impact, but it is considered more likely that it was the effect of a large amount of fresh water suddenly entering the North Atlantic as the ice in North America melted. This altered the salinity of the ocean, slowing down the currents which transport heat from the South to the North Atlantic.

Orkney currently has a temperate oceanic climate, with mild winters, very little snow, short cool summers, strong winds and comparatively high rainfall all year round. Both cereals and vegetables grow well in Orkney, although cereal crops are at risk from the short growing season and from damage by the strong winds. Bere barley and oats are the traditional grains. The various islands in the Orkney archipelago differ slightly in what does best.  Low said in the late 18^th century of South Ronaldsay: “The corns of this island are generally late in ripening, and the crop rather precarious when the season proves broken and the harvest rainy; however this is not so much the case but this furnishes vast quantities of meal and malt even in years when many of the other isles are but poorly off in this respect, so that in general they can spare more grain than any other of the S. Isles in proportion to the bulk of their island and extent of arable land.” (Low 1774 pages 24-25). In the past, Orkney and Shetland traded extensively with Norway, exchanging grain and malt for timber.

The Old Statistical Account, also compiled in the 18^th century, records much the same vegetables as today growing in Orkney:   “…in the account for the parish of Birsay and Harray, Orkney: ‘The gardens will produce early cabbage and colliflower; as also onions, leeks, garlick, parsnips, carrots, turnips, and small salad herbs…’ This minister is probably writing about his own garden.”(Maisie Steven 1995 page 37); while Low remarks that “… in no place do potatoes thrive better than here [South Ronaldsay], ” (Low 1774 page 49-50).

If the Gulf Stream does shut down completely because of global warming, Orkney may end up with a different kind of climate, at worst subarctic/boreal (Dfc), similar to present-day Tromso in north Norway, which lies at 69 degrees north, i.e. 350 km north of the Arctic Circle. In other words, things would get significantly colder in these latitudes, perhaps up to 5 degrees colder, especially in winter.

That’s not to say we won’t be able to grow anything without a solar-powered greenhouse. I have stated my concerns about hi-tech indoor gardening in a politically unstable world elsewhere. Overpopulation, as well as the climate crisis, means that there certainly won’t be enough agricultural land available to feed everyone, so things like vertical farms will have to be tried. But it would probably be a good idea to grow as much food as we can without the help of technology. Fortunately, that seems to be possible. The Financial Times published an article on ‘Arctic Gardening’ in November 2024. Their photo of a woman with handfuls of carrots, standing against a background of abundant cabbage and parsley, grown in the Lofoten Islands (Norway, 68-69 degrees north) was impressive. This woman mentions growing kale, pak choi, green beans, parsnips and strawberries. She recommends sowing outdoors so that the plants have an opportunity to adapt to outdoor conditions. Another contributor recommends growing perennials because their root system is already established when the short growing season starts. The usual techniques are mentioned: drainage, planting windbreaks and using south-facing exposures. Potatoes were mentioned later on. Barley will grow in these regions although the short growing season is a problem.

So it can be done. But thinking ahead, a greenhouse might be a better investment in Orkney than a grapevine…

“A Tour thro’ Orkney and Schetland in 1774”, George Low

“Parish Life in Eighteenth-Century Scotland: A Review of the Old Statistical Account”, Maisie Steven 1995