Category Archives: Species

Fen nettle

Nettle (Urtica dioica) is the Jeckyll and Hyde of the home garden. It has no neutral qualities, only excellent and abominable ones. On the negative side, they spread aggressively by seed and underground runners, and attack anyone who dares try to weed them out with hypodermic syringes full of irritants. And as the leaves mature, they form microscopic stones called cystoliths that lodge in the kidney to form kidney stones. On the positive side, it is nutritious and tasty, yields fibre and medicine, dries and stores easily, is an important plant for wildlife and accumulates a suite of minerals that makes it one of the best plants around to go in your compost heap.

Fortunately, there is a way to get all of the good qualities of nettle with far fewer of the negative ones. It’s called fen nettle, a subspecies of regular nettle called Urtica dioica galeopsifolia. More on this later…

There is a long tradition of using nettles in Scotland. Bronze Age bog bodies have been recovered wearing clothes made from nettle fibre. St Colmcille, who spread Irish Christianity to Scotland in the sixth century, is reputed to have lived on nettle pottage after learning the recipe from an old woman he encountered cutting the plants. Legend tells that a servant, perhaps with less faith in the wisdom of old women, mixed meat juice into the broth from a hollow spoon that he used to stir it. Samuel Pepys was served nettle porridge on his travels through the Highlands and Sir Walter Scott mentions the practice of forcing nettles under glass in Rob Roy. Anywhere in the world where nettles grow (and that is to say, almost everywhere), there is a tradition of using them. St Colmcille might be given a run for his money as the patron saint of nettle-eating by the Tibetan poet-sage Milarepa, who subsisted on them so much that his skin is said to have turned green!

Milarepa. I haven’t experienced this side-effect of a nettle-rich diet so far.

Nettles have a distinctive, earthy taste that I didn’t like when I first tried them but have grown to love. The part to pick is the tips: roughly 10 cm of growth where they are still soft and break off easily. Wearing gloves helps if you don’t want to be stung. You’ll be glad to hear that even very brief cooking melts the stinging hairs and renders them powerless.

My main use for nettle tops is as a pot herb: they add a depth of flavour to leaf sauce that I look forward to every year. Whole, they are good fried or steamed, either on their own or mixed with other spring shoots, or on top of a pizza. They make a great filling for ravioli or maki. The traditional nettle soup is always worth making, although I tend to round it out with other leaves. Make a potato soup, throw in nettle tops and cook for just a couple of minutes before blending. Miles Irving, the author of Forager recommends instantly chilling the soup in a metal container plunged into cold water to preserve the colour and flavour. Dave Hamilton gives a recipe for nettle haggis on Self Sufficient-ish, while forager and herbalist Monica Wilde uses the seeds.

If you have more nettles than you can use they are easy to dry by spreading them out in a well-ventilated space. The dried tops can be crumbled and stored, to add nettly goodness to soups and stews throughout the year. Dried nettles also make a great tea, and blends well with mint. Fresh ones can be fermented into a refreshing ‘beer’, with no more added ingredients needed than sugar, yeast and a bit of lemon juice.

Dried nettles

Nettles are so common that it may be better to forage them than give up space in your garden for them, but there is one big advantage to having your own patch. As shoots grow older they develop harmful cystoliths (hard deposits in the cell walls) and they should not be picked after they begin flowering. You can extend the season by cutting the patch down. It won’t be long before it is producing tender regrowth. This makes nettle one of the best ‘dual use’ food/green-manure crops.

This is where the fen nettle comes in. If you are going to deliberately grow nettles in your garden, wouldn’t it be great to have one that had all the taste, nutritional and wildlife qualities of nettle, without those pesky stings? Well, you can! Fen nettle is a subspecies of stinging nettle that grows in wet places across Europe. Besides having far fewer stinging hairs, it even has, in my experience, a better growth habit for the garden – more upright and less aggressively spreading.

There are two ways to propagate fen nettle, both of which I offer in my seed list. The first is by seed, but here there is a risk that the results will be a cross between fen nettle and wild stinging nettle. All nettle plants that spring up near my fen nettle patch get scrutinised with great suspicion, then either disposed of or transfered to a pot to grow on for further examination! The other method avoids this risk. Those spreading rhizomes which can make nettle such a pest make it incredibly easy to propagate: just dig up a piece and transfer it to a new home.

Fen nettle leaves.
Stinging hairs on stinging nettle.
Fen nettle stem.

Snowbell (Allium triquetrum)

This seems like a good time of year to post about snowbell (Allium triquetrum, also known as three cornered leek), one of the most useful plants in the forest garden in winter. A strange quirk of nature means that many of the best plants for the Scottish forest garden in the depths of winter come from the Mediterranean region. Native plants have almost all quite sensibly opted to lie dormant at this time of year, making for an abundance of roots but few leaf crops. Mediterranean plants are used to mild (but not entirely frost free) winters and punishing summers, so they have evolved to do most of their growing in winter, saving the summer months for flowering and seeding.

Of course, this means that many Mediterranean plants simply can’t cope with Scottish winters, but a surprising number can, including some familiar crops such as artichoke, wall rocket, king’s spear, red valerian and rosemary, all of which put on significant growth in winter. The general rule of thumb for Mediterranean plants is to give them a good, well-drained soil, since their biggest enemy is winter wet.

Of all these plants, snowbell is the most productive during winter in my garden, producing a significant amount of long, oniony leaves, adaptable enough to go in stir fries or salads, or to accompany leeks, kale, sea beet, radish leaves, Serbian bellflower, celery and wintercress in a welcome dose of ‘green‘. Many alliums start early and I expect wild garlic and chives to be producing before the end of February, but only snowbell grows really strongly in the darkest months around the solstice.

As with most species, locally adapted plants are a definite plus. I got my first plants from Cornwall, and they suffer noticeably in northern Scottish conditions. I then found plants growing locally, with many generations of adaptation to local conditions under their belt. The pictures below show the difference.

Cornish snowbell in winter
Scottish snowbell in winter

One risk with snowbell is that, as its name implies, it looks quite a lot like a white variety of bluebell or wild hyacinth (Hyacinthoides non-scripta), which is poisonous. Once you get your eye (and nose) in, there are many differences, including snowbell’s longer, softer, onion-scented leaves, differing arrangement of flowers and distinctive green lines down the centre of every petal, but it is worth being aware of the danger and, obviously, not to have bluebells in your forest garden.

silverbell flowers
Bluebells and snowbells side by side

As with all the articles on this site, this one is about using snowbell in a cultivated space. It is illegal in Scotland to plant any non-native species (including snowbell) in the wild or to allow it to escape from your garden to the wild, so consideration should be given to the potential for this before planting it, even in a garden. The snowbell in my garden has not been difficult to keep contained, but bear in mind that invasiveness varies according to local conditions and this may not be true for you in your country or part of the country. There is also another plant which is similar to and sometimes confused with snowbell. This is few-flowered leek or onion (Allium paradoxum). I would not recommend planting this even in a garden as it is extremely invasive thanks to the mass of bulbils that it produces in place of flowers.

Growing and eating silverweed

Silverweed has a long history as a cultivated crop. It was sufficiently important, in the landscape-scale agro-ecology of the pre-colonial Pacific North West, that access to good patches was controlled by law. Closer to home, Alexander Carmichael says in the notes to the Carmina Gadelica that silverweed root (brisgean) was much used in the Gàidhealtachd before the potato was introduced. He says that it could be traded, ‘quantity for quantity’ with corn and meal, suggesting that it was equally valued nutritionally. It was considered palatable and nutritious and eaten boiled or roasted or dried and ground into meal for bread and porridge. I mostly eat it boiled and find that it has a rich, creamy taste and texture.

One eye-catching claim made by Carmichael is that at Lag nan Tanchasg in Paible, North Uist, ‘a man could sustain himself on a square of ground of his own length’ by growing silverweed. Unfortunately he makes no mention of cultivation methods, but I suspect that he is talking about a lazy bed system, in which a raised bed is heavily mulched with seaweed. This would make sense both as a way of growing heavy yields of, well, anything, on Uist (and was later used there for growing potatoes), and also because silverweed is well adapted to growing on the seashore and is often found there. Like many species adapted to growing on shifting sediments, it spreads strongly via runners, which help it to bind the soil together and adapt quickly to disturbance. It’s a habit which has helped it adapt to other, novel habitats, such as the frequently-disturbed, heavily-salted margins of roads.

Variation between clones: silverweed…

…and not-so-silver weed

It’s also a habit which makes it, as anyone who has tried will know, difficult to replicate past cultivation methods in an ordinary garden. It will take over any veg bed it is planted in in short order. It will also naturalise happily in grass, but then it becomes very difficult to dig out the starchy roots which are its main edible part. A further complication, if anyone was really serious about adapting this plant to cultivation, is that it’s hard to maintain and breed separate lines of a plant that is hard to contain as an individual even in a pot, never mind in a patch of soil.

This might explain why, despite having been interested in silverweed ever since I first tasted its roots, I haven’t made much progress in fitting it into my garden. However, I did make one useful discovery recently which should make the task somewhat easier. I have a number of individual clones, collected from around the country, which I keep separate by growing in buckets (escaping from a bucket is nothing to this Houdini among plants, but you can thwart it by winding its runners around inside the rim of the bucket, making sure they never touch the ground). One winter I tipped out one of these buckets, and discovered that the thickened roots had almost all formed right at the bottom – making it easy to nip off the best ones to eat. I then put some compost in the bottom before putting the whole mass back in on top. They respond well to this treatment, and also become more willing to produce seeds, which I plan to use to start new pot-colonies.

brisgean
seeds

It’s not really in the spirit of forest gardening, in which the plants are meant to be more integrated than this. It’s also a challenge with other shifting-sediment plants like asparagus, which rely on their environment to deal with competitors and are intolerant of any competition. However, I can picture an analogue of the lazy bed, with a well-edged raised bed, regularly topped up with the abundant compost produced by a forest garden. This wouldn’t have the bottom-of-the-bucket effect but would probably create a soil loose enough to be dug easily.

Incidentally, I haven’t been following my usual practice of giving Latin names alongside the English ones in this post. This is because the naming of silverweed is, frankly, a mess. It’s an aggregate species which can be divided into many or lumped into one according to taste and fashion, and systematists can’t even agree on which genus to place it in. It is (probably) called Potenialla anserina today, but the genus name Argentina is also commonly used.

Silverweed flowers by S. Rae from Scotland, UK, CC BY 2.0 via Wikimedia Commons

Honey under ground
Silverweed of spring.

Honey and condiment
Whisked whey of summer.

Honey and fruitage
Carrot of autumn.

Honey and crunching
Nuts of winter
Between Feast of Andrew
And Christmastide.

Carmina Gadelica, from translation edited by CJ Moore, Floris Books 1992 p366. Thanks to Alison Tindale of the Backyard Larder for putting me on to this reference.

Saltbush (Atriplex halimus)

I first came across saltbush (Atriplex halimus) at the Plants for a Future site down in Cornwall. I loved the salty taste of the leaves and spent many years trying to establish it in Aberdeen. Unfortunately we are on the edge of its range here and I lost a succession of plants, usually over winter. I think I have finally cracked it though, as my latest plant has survived many years, including temperatures down to -11°C this winter. In common with many Mediterranean plants, its real enemy is not so much winter cold as winter wet, so the key to survival is giving it a really well-drained spot. I have mine at the apex of a raised bed, sheltered from the rising sun in winter to minimise frost damage. Planting early in the growing season helps to give the plant the best root development by the time winter comes. If you acquire a plant in late summer, autumn or winter, keep it inside until you can plant it out in spring.

You might want to grow saltbush even if you weren’t interested in eating it, as it’s a very attractive plant. It eventually grows to be a small shrub with silvery-grey leaves. These leaves are the edible part, with a salty tang that is nice mixed into a salad. The saltiness of the leaves does seem to vary with the time of year and the amount of salt in the soil – at least it seemed to me that they were saltier after I mulched my plant with seaweed one year. The best way to pick the leaves is to nip out whole growing tips. This gives you the tenderest leaves and encourages the production of more. It also helps to keep the plant compact and stop it getting leggy. A cultivar called ‘Cascais’ is worth getting hold of as it has larger leaves and shorter internodes than the wild type, giving you more leaf and less stem.

One advantage of saltbush is that it is very easy to grow from cuttings, which means that you can take a backup copy, as it were, if you’re worried about losing your main plant over winter. In the UK, I can send a cutting to anyone interested in giving it a go – see my seed list for details.

My top 30 forest garden plants

One of the questions I am asked most often about forest gardening is which plants to start with. I find this a hard question to answer for a number of reasons. One is that the key to a forest garden is diversity, so the answer I really want to give is all of them, which I realise isn’t very helpful. The second is that it’s a very individual matter, depending on the gardener’s climate, site, taste buds and access to plants that can be foraged. For instance, I don’t grow brambles (blackberries), since I know of several spots within cycling distance where I can pick to my heart’s content – but if I couldn’t get them wild I would most certainly grow them.

Despite all that, the question keeps coming up again, so here – with all the caveats above and in no particular order – is my personal top 30, of plants that are productive, easy to source and easy to grow. It might not be the same as yours, but it’s a place to start.

Wild garlic (Allium ursinum)
Very shade tolerant, very reliable and very productive once it gets going, wild garlic is available from February to June and provides a garlic flavour when raw or a bulk vegetable with an oniony taste when cooked.
Growing and eating wild garlic

Kale (Brassica oleracea)
With year-round leaves and delicious, nutritious flower shoots in spring, kale is one of my most reliable pot herbs. Both biennial and perennial varieties are available.
Daubenton’s kale – growing and cooking
Perennial kale breeding

Chives (Allium schoenoprasum)
There is a huge number of leafy alliums that can be grown in the forest garden, but this traditional one is still one of my favourites. I use the flowers as much as the leaves, cooked as much as raw.

Perennial leeks (Allium porrum)
Complementing annual leeks nicely, perennial leeks can be bred quite easily from traditional annual varieties or grown from bulbils produced by cultivars such as Babington leek.
www.facebook.com/scottishforestgarden/posts/2767925186556620

Celery (Apium graveolens)
Half way between a herb and a vegetable, hardy celery provides stems, leaves and/or flower shoots at almost any time of year. I never use it on its own but to add flavour and bulk to pot herbs, soups, stews and stir fries.
Hardy celery

Sea beet (Beta vulgaris maritima)
The ancestor of sugar beet, beetroot and chard, sea beet is hardy, nutritious, tasty and productive. I use leaves in autumn, winter and spring, moving to the immature flower heads (steamed and then dressed with sesame oil, soy sauce and lemon juice) in summer. Just remember to let some of them produce seed as it grows better as a biennial than as a perennial.
leaf beet
https://www.facebook.com/scottishforestgarden/posts/2390524570963352

Giant bellflower (Campanula latifolia)
Giant bellflower provides leaves, shoots and roots and has the advantage of being more shade tolerant than most bellflowers.

Miner’s lettuce (Claytonia perfoliata)
A mild-tasting salad leaf, miner’s lettuce needs some ground disturbance to keep seeding itself. Once established, it will pop up wherever there is a gap.
Claytonias – miner’s lettuce, wood purslanes and spring beauties

Fawn lilies (Erythronium)
A useful shade-tolerant starchy root crop. The cultivar ‘Pagoda’ is large and productive and very pretty too.
Eating dog’s tooth violet

Potato (Solanum tuberosum)
Wait, what? Tatties? Yes, spuds are perennial vegetables that grow well in the organic-matter-rich soil of a forest garden (not in deep shade, obviously). Using blight resistant varieties like the Sarpo family and growing new ones from seed allows you to grow them more like a perennial crop, less like an honorary annual.

Alpine strawberry (Fragaria vesca)
Alpine strawberries are wild strawberries that don’t produce runners. They are thus more manageable and easier to select good varieties from. Will self seed in the garden.
Alpine strawberry

Raspberry (Rubus idaeus)
My favourite soft fruit, and a natural inhabitant of the woodland edge.

Caucasian spinach (Hablitzia tamnoides)
A perennial climber with spinach-like leaves and edible shoots.

Daylily (Hemerocallis)
An easy-to-grow, attractive perennial that likes a sunny spot and produces edible flowers.
Eating daylilies (Hemerocallis)

Shiitake (Lentinula edodes)
Of the many mushrooms that can be grown in a forest garden, shiitake is my favourite – and perhaps the easiest.
Shocking shiitake

Apple (Malus domestica)
A productive and versatile fruit that keeps well into the winter. I use it for cooking, baking and making dried apple rings.
Applemania
In Praise of Pruning

Sweet cicely (Myrrhis odorata)
Of the many carrot relatives with edible young leaf and flower shoots, I perhaps make the most use of sweet cicely, which has a very long cropping season and aniseed-flavoured roots, leaves, flowers and seeds.
Sweet cicely

Poppy (Papaver somniferum)
A feast for the eye, for the pollinators and for the stomach, poppies produce nutritious, oil-rich seeds and pop up everywhere to fill any temporary space in the garden.
Opium poppy

Japanese plum (Prunus salicina)
Japanese plum makes the best fruit leather, is absurdly productive and fruits earlier than traditional domestica plums.
Japanese plums

Parsnip (Pastinaca sativa)
Another one that you might not expect in the forest garden, parsnips self-seed around the place and produce a crop with very little effort.
Self-seeded parsnips

Rhubarb (Rheum)
A very well-known perennial vegetable, rhubarb has both more species and more uses than it is traditionally given credit for.
rhubarb

Currants (Ribes)
Forced to choose between the different currants. I’d probably go for red/white currant, which becomes sweet enough to eat off the stem if protected from birds by netting, and is a secret ingredient in many jams with its high pectin content.
Currants

Sorrel (Rumex)
The sharp, lemony taste of sorrel is found in many plants. Forced to choose, I’d go for garden sorrel (R. acetosa) or buckler leaved sorrel (R. scutatus). Or both.
Sorrels

Linden (Tilia)
Small-leaved lime is my favourite ‘salad tree’. If the growing tips are picked rather than individual leaves it will produce a supply of tender leaves for most of the growing season. Best pruned like a hedge.
Lime greens

Salsify (Tragopogon porrifolius)
Another self-seeding annual, salsify produces an abundance of artichoke-flavoured flowers.
Salsify

Broad bean (Vicia fava)
The bean that fits best into the forest garden system, growing in small cleared patches.
Broad beans

Lovage (Levisticum officinale)
Another source of shoots throughout the growing season, lovage adds an earthy/yeasty/meaty taste to all sorts of dishes.
Lovage, actually

Persian garlic (Allium altissimum)
As well as being a striking ornamental, Persian garlic is a vigorous plant, producing large clumps of mild, garlic-flavoured bulbs, available outside the wild garlic season and easy to preserve by slicing and drying.

Nettle (Urtica dioica)
Nettles can be foraged, but having your own patch allows you to cut them down for repeated harvests. There is even a non-stinging variety!

Udo (Aralia cordata)
An enormous herbaceous perennial, udo produces an edible pith for stir fries and salads and shoot tips for tempura or stir fry, or to add depth of flavour to a leaf sauce. The taste is part citrussy, part resiny.
Growing and eating udo – Aralia cordata

To source any of these, see My seeds or Other suppliers.

Hardy celery

Some plants in the forest garden are just more easy to photograph than others. Aralia spinosa spreads its delicate leaflets in one easy-to-focus plane, while pot marigold works the camera shamelessly. Celery is at the other end of the spectrum. Its sprawling habit makes it hard to get into a single coherent photo, while the fact that it puts on most of its leaf growth in autumn, winter and early spring means that the photography conditions usually consist of low light and wet, difficult-to-focus leaves.
20191031_130639
Those of us who don’t show up so well in photographs, however, can still have lots of other excellent qualities, and celery is an indispensable member of the forest garden cast. That growing season means that celery leaves are available when few others are and its flavour is a welcome addition to winter soups and stews. As with most carrot family plants, it’s the young, tender leaf shoots that are best rather than older leaves. In summer the young flower stems can also be used in dishes like stir fry and the seeds, produced in abundance, make a wonderful aromatic spice.
No matter how useful I find celery at present, I think I have only started to explore its potential as a forest garden plant. The celery I’m talking about is not the familiar shop-bought celery with its large, white, crunchy stems. That can be grown in Scotland, but only with lots of care, watering, feeding and mounding, and preferably a polytunnel. I’m talking about the smaller, leafier varieties variously called wild, herb, leaf, cutting or Chinese celery, which are used more as a leafy herb than as a stem vegetable.
Despite their differences, all these varieties are the same species, Apium graveolens. While the chunkier stem celery was clearly developed far south of Scotland, there’s no reason why a bit of selective breeding couldn’t favour the same qualities within a hardier gene pool, more adapted to a forest garden in the North. That’s what I’m working on in my garden, and celery is already responding.
The first step was to source a wide range of genetic sources. This involved navigating a bit of a minefield of names. True wild celery is Apium graveolens var. graveolens or ‘smallage’. It is a plant of wet, salty ground. Seed sold as wild celery is usually probably not true wild celery but one of the leafy cultivated celeries collectively labelled Apium graveolens var. secalinum, as opposed to the thick-stemmed var. dulce. One group of these are the Chinese celeries, also known as kintsai (which is just an old spelling of the Chinese word for celery, qíncài or 芹菜) or Nan Ling celery. Chinese celeries have generally undergone more selection than their Western counterparts. They tend to be more delicate and more colourful, and not quite so hardy. Western secalinum are called herb, leaf or cutting celery. There’s also a Dutch heirloom variety usually marketed as ‘Par-cel’ or occasionally ‘Zwolche Krul’. It’s a dead ringer for curly-leaved parsely – hence the name – and there’s a lot of confusion on the internet as to which it really is.


Having sown a range of these different kinds, I left them to it for a few years to mix up the gene pool. Celery is biennial so there is a new generation every couple of years. Now everything is well mixed, I’m starting to apply some selection pressures. There are a few qualities that I’m selecting for. Size and vigour are important of course. For stem qualities I’m looking for thickness and solidity. Some stems are hollow while others are fleshy all the way through. A few plants seem to have a degree of perenniality, surviving and growing again after flowering. Hardiness and general adaptation to my garden conditions are selected for by the environment.
You can see some of the variation here, in the range of leaf lengths, thicknesses, colours and solidity. No prizes for guessing which is my favourite one so far.
_MG_6365celery comparison
I haven’t tried selecting for a thickened hypocotl or stem base yet, but that would be the route to an equivalent of celeriac, the bulbous Apium graveolens var. rapaceum.
Although celery is ancestrally a marsh plant mine seem happy in all parts of the garden, including in a moderate amount of shade. In contrast to the traditional celery it needs next to no special care.

Claytonias – miner's lettuce, wood purslanes and spring beauties

The Claytonias are a very useful group in the forest garden, being very palatable species whose natural habitat is woodland.

Claytonia perfoliata, miners’ lettuce, is unusual in the genus in that it is an annual rather than a perennial. It is often grown in greenhouses in Britain as a winter salad, but it is much less commonly found grown outside. It can be difficult to get established as a self-sustaining, self-seeding population, but once you manage it makes an excellent early salad that maintains itself with little fuss. Getting a locally adapted strain might be the key to success: I spent a long time trying it with little luck until I found a population self-seeding itself in the nearby university car park, prospering despite the chemical warfare waged against it by the university’s estates department. Seeds from these plants germinate earlier and grow more vigorously than any that I have ever bought from the seed trade.

Miners’ lettuce is mild-flavoured and succulent so it makes an excellent bulk ingredient for salads. All parts are edible, including the leaves, stems and the unusual-looking large fleshy bract around the flowers. They can also be cooked, for instance in stir fries. In my garden some plants germinate in autumn and are available in small quantities through the winter. Others germinate in early spring and by March I have a good stand of it. It will grow in the open or in partial shade and likes a well-watered soil. It is rich in vitamin C: the name comes from its use against scurvy by gold miners in California’s gold rush. There are two closely related species: C. parviflora and the deep red C. rubra. I can’t find any information on the edibility of these but I’m sure they would be worth investigating: C. rubra in particular would look very striking in a salad.


Claytonia sibirica, pink purslane, is a perennial equivalent of miners’ lettuce. It is widely naturalised in Scotland, to the extent that there are locally named varieties, such as the white-flowered Stewarton flower found in north Ayrshire. It tends to form an extensive carpet in both broadleaf and coniferous woods: this looks spectacular when it flowers. In the forest garden it can be used in the shady areas under crop trees. The flavour is stronger than that of miners’ lettuce – something like raw beetroot.

Other species listed in the literature as having edible leaves include acutifolia, caroliniana, exigua, lanceolata, megarhiza, scammaniana, tuberosa, umbellata and virginica.
Finally, a number of species have edible roots, which go by the name of fairy spuds. Species include acutifolia, caroliniana, lanceolata, megarhiza, tuberosa, umbellata and virginica I haven’t managed to grow or try any of these yet but forager Euell Gibbons described C. virginica roots as tasting like sweet chestnuts when cooked.

Turnip-rooted chervil

I was being a bit of a pig in the allotment recently. Wild boar are one species that definitely didn’t get the memo about no-dig gardening. They have worked out one essential fact about the winter forest: the ground is where all the good stuff is. Their rootling behaviour – essentially ploughing up the ground looking for hidden bounty – looks destructive, and in some ways it is. Where densities are high they can cause an 80-95% reduction in herbaceous cover and the local extinction of some species. In other ways, their activity aids the health of the forest. Like any sensible pig, they prefer to target abundant species where they can be sure that all that work will be rewarded (you try digging up the earth with your nose, after all). As such they preferentially target plants with imperialistic tendencies, such as bracken and willowherb rhizomes or carpeting bulbs such as bluebells. This knocks back these aggressive spreaders, making space for a greater variety of species, and a number of studies have shown that over the long term species diversity is higher in areas with wild boar than in those without.
1024px-wildschwein_12.4.2008_117
Similarly, in the forest garden, there are some crops where a good rootle is the only way to harvest them at some times of year, and the resulting soil disturbance helps to make room for a range of self-seeding species that tend to get crowded out in entirely undisturbed, perennial communities.
One of these is turnip-rooted chervil, or plain root chervil (Chaerophyllum bulbosum), a biennial root vegetable in the carrot family. If you’ve never heard of it, that’s probably because it has a few oddities in its life cycle which mean that it has never been cultivated widely. The first of these is that the seed needs stratification (winter cold) in order to germinate, and loses its viability very quickly in dry conditions (like seed packets). This means that fresh seed needs to be collected every year and sown very soon after, in the autumn. This makes growing it in rows in a crop rotation quite awkward. One option is to simply allow it to self-seed around the garden, which it does very readily and which eliminates all the worries about sowing and stratifying.
The second problem is that it sprouts early and dies back early, generally at the first hint of dryness. When it dies back it does so without leaving a trace of where it is. This isn’t a problem in labelled rows, but definitely is when the roots have planted themselves randomly around the place. It isn’t helped by the fact that many people reckon the the flavour of new roots is poor compared to ones that have sat in the ground for a few months in cold conditions.
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All this leads to two main strategies for growing root chervil. The first is to sow it in annual beds in autumn, well marked and labelled. It starts to germinate here in early March, well before most crops. It then dies down by June, giving room for another crop, perhaps something like oriental greens which benefit from a late sowing so as not to run straight to seed. Finally it can be harvested over the winter. Some gardeners report problems with rodents getting at the stored roots, in which case a month in the fridge is also enough to improve the flavour. I find that chervil roots have a starchy, chestnut-like flavour that I enjoy a lot.
The other option is to let the plants take care of the sowing themselves, but this means that you are likely to have very little idea of where exactly they are by the time you want them. Until, that is, the roots have to give themselves away in order to grow for the new season. This is when you can harvest a great delicacy. A quick rootle will give you a pile of roots with young growth attached. There is no need to separate these as both parts are edible, just wash them well. By this time the flavour of the root has changed completely. The starch has been broken down into sugars, mobilised for growth, and the taste is now somewhat carroty and very sweet. It is impossible to get them out without a degree of soil disturbance, but, as the wild boar demonstrate, that is not entirely a bad thing in the forest garden.
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Whenever you dig them up, it is worth keeping the best roots to transplant to another bed for seed production. The roots show a lot of variability, in size, length and form. The default seems to be a round shape, presumably explaining the ‘turnip-rooted’ part of the name, but a proportion have an elongated, carrot-like shape which seems to be associated with higher yields. Given that you are likely to have to maintain your own seed line if you want to grow this vegetable at all, you might as well take the opportunity to improve the stock and adapt it to your own conditions as you go.

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Sprouting roots with the best separated out for replanting


I am always astonished at what a vigorous shoot comes out of a little chervil root. From a root usually no more than a few centimetres long they throw up seed stems over three metres tall. These can be very dense and with little leaf, so most of the nutrients required must be coming out from the root. This matches with the starchy flavour and a dry weight that is about 40% of it’s fresh weight. Chervil roots are clearly very dense nutrient stores. As such they could be seen as contributing to nutrient storage in the system as a whole. I am never too worried about surplus chervil roots that pop up and run to seed in unexpected areas of the garden: they are easily pulled out and put on the compost heap and don’t seem to bother the plants around them excessively as they are running on stores.
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Root chervil seed heads against a bright Aberdeen sky


There is more on TRC at:
https://www.cultivariable.com/instructions/root-crops/how-to-grow-root-chervil/
https://hort.purdue.edu/newcrop/proceedings1990/V1-422.html