Tag Archives: perennial vegetables

Eating rhubarb flowers

There’s an unusual perennial vegetable lurking unsuspected in many gardens at this time of year: rhubarb flowers. You should remove the flower stems from rhubarb to stop it wasting its energy on seed production in any case, so instead of chucking it on the compost, you could use it, as they do in the far east, as an exotic seasonal ingredient.

rhubarb flower stems

The secret to preparing rhubarb flowers is to know that the tiny individual flowers that make up the head do not contain any oxalic acid, the substance that makes rhubarb so sour, but the flower stem does. The stem is a branching structure that goes right inside the head so you’ll never get it all out, but if you just cut off the most accessible bits you’ll have got rid of most of it. Also be sure to remove the stem leaves, which are presumably as poisonous as the basal ones, and the papery bract which surrounds the flower head.

rhubarb flowers

The result is still sour, but interestingly rather than overpoweringly so. It goes best in dishes where there is a sour element and you can often leave out vinegar or lemon juice from a recipe in compensation. I find it delicious boiled for four or five minutes with broccoli sprouts, then drained and served with oil and salt over the top, leaving out the shake of lemon juice that I would usually add. It also goes very well in a stir fry.

Since a flower head will contain some stem and therefore some oxalic acid no matter how carefully you prepare it, it would be a bad idea to consume excessive amounts of them. This is also true of the rhubarb stems that are more normally eaten.

More on rhubarb in Rhubarb and elderflower jam, and a surprise.

Growing and eating wild garlic

Very few of the really shade-tolerant vegetables are as productive, versatile and useful as wild garlic (Allium ursinum), also known as bear garlic, ramps or ramson. When I was young, on a family holiday in Wales, I discovered a wood carpeted with ramsons. Overwhelmed by such exuberant bounty, I stuffed my pockets with leaves. In the car on the way home my parents noticed a certain odour taking over the space and after a quick search my foragings were evicted. I suppose it could have been worse, it could have been me. Nowadays I have my own tame patch of wild garlic in my allotment and I can harvest it when I like.

Wild garlic

As with many perennial crops, there is a useful synergy between wild garlic and the cultivated kind (Allium sativum). It starts to be ready just as stored bulbs are usually running out, some time in February or March, and runs through until about June. Wild garlic can be used pretty much anywhere you want a garlicky flavour, with the caveat that the flavour doesn’t survive cooking for long, so you generally need to add it to cooked dishes near the end. Ramson pesto packs quite a punch. I like to chop leaves into salads: whole leaves are a bit strong to eat in bulk but chopped roughly and mixed with other leaves they are delicious. Layering a few leaves into a sandwich works well too. For some seriously local food, you can try using it to supply the garlic flavour in broad bean hummus.

However, if its garlic flavour were the only thing that wild garlic had going for it, it would be best regarded as a herb and grown in a small patch in a shady corner. What makes it useful as a bulk vegetable is the very fact that it loses its garlic flavour when cooked for more than a few minutes, leaving a very tasty, oniony green. As such I use it anywhere where I would use onion, particularly as the base of a sauce, be it pasta, curry, stew or soup. You can also substitute it for spinach for delicious variations on dishes such as lasagne. It makes an excellent pot herb, either on its own or mixed with other leaves that are available at the time, such as annual and perennial kales or leaf beet. One thing to be careful with is that wild garlic quickly develops a rather unpleasant burnt-onion taste if allowed to dry out while cooking, so you need to take care to keep it moist. In our household we love wild garlic on pizza but we always layer it at the bottom so that the other ingredients protect it.

Almost all parts of wild garlic are usable, including the leaves, stems and flowers. The flowers look amazing in a salad. The bulbs are also usable once the leaves have died down, but they are not as good as the bulbs of cultivated garlic and they don’t store very well once lifted. And of course, if you eat all the bulbs then you don’t get the other parts. That said, if you have a good supply of them you might want to try the recipe for pickled wild garlic bulbs that can be found – with many others – on the excellent Eat Weeds blog.

You can harvest wild garlic simply by pulling off individual leaves or, for less garlicky hands and to speed things up, you can cut a clump at a time with scissors. I generally put my wild garlic leaves in a bowl of cold water for five minutes as soon as I get home, to preserve and wash them. They’ll then keep for at least a week in the fridge. Another way of harvesting that gives a slightly different product is to dig up a clump and then prepare the individual plants by cutting off the roots and removing the sheath of the bulb. The whole thing then hangs together in a sort of ‘spring onion’ version of wild garlic. Fried in plenty of oil and dipped in a sauce these are gourmet food indeed.

wild garlic clump, separated

wild garlic clump, separated

Ramsons are an easy plant to grow, flourishing in the parts of the garden that most other plants avoid. They are a plant of deep woodland, so they like plenty of shade and a moist, humus-rich soil. Once you have got them established they will generally self-seed (to the point of nuisance if they weren’t so edible). Their habit of dying down in the summer makes them easy to manage as you can choose this time to top-dress them, mulch them or hoe over the top of the bulbs. They can even be used in a strip as a bit of a barrier against the spread of other plants. During the spring they suppress other plants by the strength of their growth and during the summer you can hoe the strip. Ramsons are capable of growing through quite a thick mulch: their leaves form green spikes that punch up through mulch before unfurling. Alternatively the dormant period is long enough that you could fit in another crop or a green manure, or interplant wild garlic with another perennial that makes use of the later part of the year.

wild garlic - just emerging

wild garlic – just emerging

Wild garlic will tolerate growing in the open, but as soon as there is hot sun its leaves will burn off and it will retreat to its bulb. It is worth growing some wild garlic in the deepest shade you can find, in which case it will persist until midsummer. Wild garlic can be raised from seed or, more easily, grown from bulbs. The bulbs do not store like those of cultivated garlic, they dry out and die quite quickly if they are not stored moist. They transplant very well ‘in the green’ (while the bulbs are growing), which also avoids the problem of forgetting where you have planted the bulbs! If you are in Scotland, don’t forget that it is legal to pick leaves, flowers and seeds for your own use without the owner’s permission but not to uproot a plant (e.g. by transplanting bulbs) or to harvest commercially. If you want to do either of these you will have to ask the owner.

One word of warning, whether you are foraging wild garlic or growing it. While wild garlic is entirely edible, it can be growing in with leaves of plants that are quite poisonous, as most of the spring bulbs are. It is hard to mistake wild garlic for anything else when you look closely – the combination of the broad, soft leaf and the garlic smell is unique – but if you are picking lots of leaves you might become a little careless. In the photo below you’ll see a patch of poisonous snowdrops growing in about the wild garlic, so if you are foraging, take care, and if you are growing I would recommend removing any snowdrops, bluebells or other spring bulbs from the same bed.

wild garlic 02

Photo: Monimail Tower woodlands from Scottish Wild Harvests Association’s Forage In Fife.

In North America, the name ramps has transferred itself to a similar-looking plant, Allium tricoccum, also known as wild leek. It’s a fascinating piece of convergent evolution. The two species are actually rather distantly related within the Allium genus, but by adapting to the same woodland niche they have come to be very similar in both looks and behaviour. Both are spring ephemerals, coming up and dying down early to make the most of the spring sunlight before the trees leaf up. Both carpet the ground and have broad, delicate leaves, adapted to capturing as much light as possible and dropping the usual allium adaptations to drought and strong sunshine. Despite this there are differences reflecting their divergent ancestry. The North American ramps has shallower bulbs than the Eurasian and the whole plant is more commonly used rather than just the leaves. The leaves and bulbs become tough and inedible and start to die down once the plant starts flowering, unlike A. ursinum, in which leaves and flowers occur together.

Further reading: Forest Gardening; Real Spring Onions.

Real spring onions

Last year was the warmest March on record: this year it has so far been the coldest. Spring ain’t what it used to be. None the less, it’s reliably time to harvest the ‘spring onions’.

I don’t mean the things you buy in the shops as spring onions (or scallions) since I don’t grow them. Let’s face it, onions are a pain to grow from seed. You need lots of added soil fertility and fanatical weeding of things that look regrettably similar to grass seedlings. Then, just as they are starting to look after themselves, you dig them up and eat them. By this time it’s usually August, which isn’t spring, not even here in Aberdeen.

tree onion

tree onion

Fortunately there are two perennial vegetable species which produce excellent spring onions even when it’s still snowing and with very little fuss for the rest of the year: tree onion (Allium cepa proliferum) and welsh onion (Allium fistulosum).

Tree onion is the same species as the ordinary onion. A lot of allium species can produce either flowers or tiny bulbs called bulbils (or both) in their flower heads and tree onion is a kind of onion that goes for all bulbils. These often sprout when they’re still on the plant, giving it a tree-like appearance. The stem then usually falls over, giving the plant another of its many names – walking onion – as the bulbils put down roots and the plant ‘walks’ around the garden. It also reproduces by bulb division underground, like a shallot or a daffodil.

tree onion divided

tree onion divided

This gives two ways to exploit tree onions for spring onions. First you can dig up the parent plant when it resprouts in the spring, divide out some of the bulbs and replant the rest. The other way is to gather the bulbils when they are produced later in the year and plant them out into a bed where they will grow on into very well shaped spring onions. It’s kind of like having a free supply of onion sets for spring onions and yet another name for this plant is ‘topset onion’ (You can also let them grow on into bulb onions, but they tend not to be very big.). You can plant some in the autumn for spring growth as they are extremely hardy but they will also keep well if you store them in a cool, dry place, so you can make successional sowings later on in the year too.

Welsh onion is a different species from regular onion but it’s very similar to tree onion. Instead of bulbils it produces a rather fleshy flower head which can also be used as a flavouring or left to produce seed (picking the flowers stops the plants producing seed and diverts their energy back into making bulbs). Like tree onions they divide underground and can be lifted and divided as spring onions in March and April.

welsh onion divided

welsh onion divided

Both species can also be harvested by picking leaves in the summer. I find that welsh onion makes bigger and more regular-sized spring onions by division and tree onion is better for leaves, partly because you can use the bulbils to produce a really dense patch. So the best use is probably welsh onions for division in the spring and tree onion for leaves and sets for growing on. If you allow welsh onions to flower you will be very popular with the bees.

Real spring onions can be used in all the same ways that you would use the seed-grown ones. My favourite is spring onion sambar: you fry a large handful of whole spring onions until they are soft, then add tamarind, coconut and spices to make a sauce and simmer for a few minutes. It’s a great way to forget the sleet driving at the window.

Perennial wall rocket

I first came across Diplotaxis tenuifolia at a seed swap on my allotments site. It was labeled ‘wild rocket’ so, thinking it was nothing more than a wild version of the familiar salad leaf (also known as rucola or arugula), I sowed a row and more or less forgot about it. When it grew, there was nothing to make me change my mind. Its attractive, lacy leaves looked like a finely-cut version of rocket and that distinctive peppery taste that you either love or hate (I love it) was there.

But then it did a very un-rocket-like thing. It kept on growing. And growing. The frustrating thing about ordinary rocket is that it just wants to flower and seed, so the period during which it can be bothered producing leaves is little more than a month. My new rocket flowered profusely with lemon-yellow crucifer flowers that the hoverflies clearly loved, but it also went on and on producing new leaves, eventually making a bushy, if floppy, plant about a foot high. Finally, I made some discreet inquiries into its parentage.

Image by T. Voekler on Wikimedia Commons

Wild rocket, it turns out, is just one of the names of D. tenuifolia, along with sand rocket, sand mustard, Lincoln weed and perennial wall rocket. These give a clue to its habitat. It likes a free-draining soil, be it sandy or rocky, and doesn’t need much in the way of water or nutrients. Ideally for my forest garden setup, it will also tolerate some light shade. It is also perennial, meaning a much longer period of leaf production than annual rocket. It is still growing in my garden in Aberdeen, despite several heavy frosts, and last year it went on until the first snows. It is also very early to come back into production once winter is over.

The taste of wall rocket is much like that of its annual cousin, but with a hint of cabbage and more of a kick. The leaves get stronger as they get older, but there is a continual production of fresh leaves, so I don’t find this matters much. You can cut the plant down to encourage a bigger flush of new leaves. If you have lots of older leaves, you can blanch them in boiling water for about 30 seconds which reduces the heat a bit. Cooking them for longer than this isn’t recommended as they lose their flavour entirely. My favourite uses are in salads, sprinkled on pizzas once they come out of the oven and as a topping for pasta sauces. You can also make soup with them in the same way as you make watercress soup.

The final surprise that wall rocket had for me came when I tried to move a couple of plants. They had deep, fleshy tap roots, which means that they probably act as dynamic accumulators in the garden ecosystem.

Garlic chives

We’ve had a couple of frosts now, but the garlic chives (Allium tuberosum) are still going strong – and still hoaching with hoverflies on a sunny day. I think of garlic chives as a sort of late-season wild garlic (Allium ursinum). They have all the same edible parts: leaves, flowers, seeds and (rather fiddly) bulbs. They also have much the same uses, imparting a garlicky tang to soups, salads, sauces, pestos – pretty much anything you like. They also have the same limitation, which is that cooking breaks down their flavour quite quickly, so it’s best to add them near the end of the cooking.

The difference is that where wild garlic is a woodland plant that prefers to lurk in the shade, garlic chives are sun worshippers. This means that while wild garlic has big, flat leaves to harvest every ray of sunshine going and rushes through its life cycle before the leaves come on the trees, garlic chives have long, thin leaves and a more leisurely approach to life. If you have both species you’ll only be without their flavour for a couple of months a year.

So long as they have their sunny spot and a well-drained soil, garlic chives are unfussy plants, tolerating drought and a wide range of soil types. They are hardy too, only dying down for a few months of the year and starting back into growth when the temperature goes above 3°C. Their main drawback is that they are so keen on flowering that they are not hugely productive: most of their energy goes into blossoming. However, their flavour is quite strong so you don’t need much, you can eat the flowers too and who could argue with all those hoverflies?

Eating hostas

One of my favourite seasonal treats from the forest garden is the hostas. No, no spelling mistake: hostas are really edible. In fact, they are a near perfect forest garden crop. Woodland is the natural habitat of many hosta species, so they like moist soil with plenty of organic matter and tolerate a considerable amount of shade. A friend tells me that they have a positive allelopathic relationship (i.e. they secrete chemicals that help each other) with apples, and since the research on it is published in Russian I’ll have to take her word for it. Hostas are no novelty nibble: they have the potential to be a major productive vegetable.

hosta clump

The best part of the hosta is the ‘hoston’, the rolled up leaf as it emerges in the spring, although many varieties are still pretty good even once they have unfurled. The best way of cooking them depends on the size of the hostons. Small ones are delicious if you fry them for a few minutes, then add a little light soy sauce and sesame oil. The slight bitterness of the hostons complements the saltiness of the soy sauce very well. Similarly, they go very well in stir fries. The chunkier hostons are better boiled briefly and used as a vegetable. In the picture below, the hostons on the right are bound for frying, those on the left are for boiling.


Hostons are best cropped by gripping them firmly near the base and snapping ones off the edge of the clump. If you can snap them off right at the base they will hold together as a whole instead of falling apart into individual leaves. The short leaf scales around the base are bitterer than the larger leaves so they are worth removing. It is much easier to harvest the hostons if the crown of the plant is a little above ground level when it is planted. It is possible to harvest the whole first flush of leaves of an established plant without killing it: ornamental hosta growers will sometimes ‘mow’ their plants to get a second flush of fresh, attractive leaves.

Later on, the open leaves can be used as a general pot herb or substituted for spinach in recipes like ‘hostakopita’. The flowers and flower buds are also edible: the Montreal Botanical Garden lists all species as edible and Hosta fortunei as the tastiest.

It seems to be an open question whether every single species of hosta is edible and therefore whether it is a good idea to try any unidentified hosta that you may happen across. The species I have eaten regularly myself are H. sieboldiana, montana and longipes. Martin Crawford lists H. crispula, longipes, montana, plantaginea, sieboldii, sieboldiana, undulata and ventricosa. Plants for a Future add H. clausa, clavata, longissima, nigrescens, rectifolia and tardiva and list no known hazards for the genus as a whole. This covers all the common ornamental species except H minor, which probably isn’t worth it anyway, and H fortunei, which must be edible since the most popular variety of it, ‘Sagae’ originally arose in hostas being grown for food in Sagae City in Japan. On the basis of that I’m happy to try any hosta myself, but if you’re going to do that, remember to try only a small piece first and test for a skin reaction by rubbing a piece on your skin before putting anything in your mouth.

Picture by ‘dcarch’ on the Seed Savers’ Forum

For more on eating hostas, there is a discussion and some astonishingly beautiful pictures of hosta dishes on the Seed Savers’ Forum. There was also a very useful article in Permaculture Magazine No. 58. It isn’t online unfortunately, but you can buy the back issue if you are really keen. A fellow wordpress blogger has also been writing about eating hostas here.

In Japan, hostas are prized as sansai or ‘mountain vegetables’, a class of plants that are usually gathered wild from the mountain and are considered to be particularly strong in vitality. There’s a great blog post about sansai at http://shizuokagourmet.com/sansai/.

Growing pignuts

Pignut is a forager’s favourite, but not easy to grow. However, it has a number of pluses that make some perseverance and experimentation seem worthwhile.

So what are pignuts? Well, to science they are known as Conopodium majus, yet another member of the sprawling Carrot Family or Apiaceae. To generations of small boys and girls, they are known as the free treat you get if you painstakingly dig down where you see the distinctive leaves. Just recently they seem to have become a fashionable ingredient, starring in some seriously foodie recipes by chefs like Hugh Fearnley-Whittingstall.


Pignuts have a lot of promise as a forest garden crop: they are extremely shade tolerant; they produce a starchy tuber, which is a bit of a gap in the forest garden repertoire; and they have a very pleasant taste and texture, a bit like a cross between a chestnut and a hazelnut. Unfortunately they also have several drawbacks, which I guess are what have so far prevented them from being domesticated like so many of their cousins.

The first is their life cycle. This isn’t a crop you sow in spring and harvest in autumn. In their first year of growth, they resolutely refuse to produce more than a single pair of leaves (technically the seed leaves or cotyledons, the ones which were always there, curled up inside the seed) even if growth conditions are perfect. At the end of the season they produce a tiny little overwintering structure called a corm, so small that you wonder what the fuss was about. The next year the plant throws up true leaves in about March but it may still take a few years for the corm to grow to a size worth bothering with.

roots and stems emerging from pignut corm

roots and stems emerging from pignut corm

The second problem is that pignuts like to bury their corms deep and then grow delicate, thread-like shoots up to the surface, making the harvesting of them quite an art. I think this is what makes them appeal to foragers, who are after all in it for the challenge as much as for the food.

Then there is the yield. The genius of pignut is that it can eke out a living, slowly increasing in a hostile tangle of other plants or in unpromising conditions. The drawback is that given a clear field and perfect conditions, it sticks determinedly to its slow and steady strategy.

pignut corms

So the good news is that if you get pignuts established in your garden, they will never need any attention again and you can occasionally dig up a pleasant treat. However, I can’t help thinking that a bit of selective breeding might produce something far more useful than this, getting round the difficulties but keeping the strengths. I’m currently growing a container full of pignuts, selecting for the size and shallowness of the corms. Since they take a couple of years to come to seed I haven’t had a lot of generations yet and can’t report any results so far, but watch this space.

The other possibility is that they could be cultivated in a way that gets round the limitations. Potatoes suffer a lot of the same problems, for instance, so we don’t usually bother growing them from seed (although you can: it’s quite easy and good fun) but instead just save a few tubers and replant them instead. It isn’t clear that the same is possible with pignut though. Instead of producing many tubers from one every year, it makes one corm, larger every year. I’ve experimented with cutting them into pieces, as you can do with potatoes, but they don’t seem to survive the process, and while potatoes hve many ‘eyes’ or growing points, pignuts have only one or a few.

A more promising line of experimentation seems to be to grow pignuts in a way better suited to their first-year growth habits. Instead of sowing out seed and having to weed the resolutely tiny plants, I sow them thickly in a tub of compost in autumn, then more or less forget about them for the next 18 months. In this time, they produce a mass of what I think of as ‘seed corms’ which can be sieved out of the compost and then sown almost as you would sow seed. An added advantage to this is that the corms stay where you sow them without getting any deeper, making them much easier to harvest.

Even grown like this, I don’t think pignut has the makings of a major crop just yet, but with enough selective breeding, who knows?

Stop that plant!

ground elder

One thing you have to consider with planting a forest garden is how the plants you put in are going to spread, either by seed or by roots and runners. No matter how much you like a plant, you are unlikely to want it across your entire site. Strategies that stop your own plants from becoming weeds will also help stop out-and-out weeds like creeping buttercup which can otherwise spread through a perennial setup very quickly.

A lot of forest garden species just quietly sit where you put them, getting a little bigger every year and patiently waiting for you to divide them. These are the swots of the class. At the other end there are plants so unruly that it’s a bad idea to even put them in. Nettle is one of these. No matter how many uses this plant has and how good for wildlife it is, it’s just not getting in my garden again. It spreads by aggressive, persistent runners and seeds itself all over the place. Then, when you try to weed, it attacks you. This is one plant I will stick to foraging [2017 update: this turned out not to be true 🙂 ].

In between, there are plants that will try to spread, but that can be contained with a bit of care. There are various strategies for this. Vigorous spreaders like mint and dittander are best planted in a pot sunk into the soil, or you will quickly have far more of them than you are ever likely to need. It’s also a good idea to divide your plot up into beds using weed barriers. I have a good network of woodchip paths which are there as much as easily hoe-able barriers as for access. Sometimes a row of a particularly vigorous but non-spreading plant, like Russian comfrey, can make an effective barrier. Plants that die down early can leave a hoe-able strip behind them: I have a row of wild garlic that I use this way.

Once you have beds, you can match plants by their spreadability. Put all the well-behaved ones together, then corral the adventurous ones in a well-barriered ‘thug bed’ and let them sort it out between themselves. It’s useful to observe in nature which plants manage to come to an equilibrium with each other: this spring I saw a mixed swathe of nettles, ground elder, wild garlic and lesser celandine – all useful edible plants with marked imperialist tendencies – in the shade of a beech tree.

With this in mind, I have finally allowed Margaret Lear of Plants With Purpose to persuade me to try ground elder (Aegopodium podagraria) in my garden. I like ground elder, at least since I discovered that the way to eat it is to pick the only-just-emerged leaves and fry them in olive oil, but I’ve never wanted it in my garden. Margaret’s variety is variegated, so it should be a little less vigorous – and also easier to hunt down if I ever take against it. [You can find out how I got on with ground elder here.]

Peach-leaved bellflower/ salad bluebell

Campanula persicifolia

Yay! My favourite salad flower started producing today. It’s peach-leaved bellflower (Campanula persicifolia), but since that’s a bit of a mouthful we usually call it salad bluebell. (Campanulas are called bluebells in Scotland. The plant that they call bluebell in England is pretty poisonous. This is why Latin names are so good!) It has a mild taste and the flowers are large and produced in abundance between now and the first frost. This means that it can be used as a bulk salad ingredient, so from this time of year our salads generally turn blue.

The whole Campanula genus is edible and further south I’m told that C versicolor tastes nicest, but persicifolia is thoroughly hardy and thrives in Aberdeen, which is what I look for in a plant.

Photo from Wikipedia Commons, with thanks to Pixeltoo.

Welsh onion

welsh onion

welsh onion

It’s practically impossible to get a photo of welsh onion flowers without a bee getting in on the act. It’s one of the big pluses of forest gardening that a plant gets to go through all stages of its life cycle, with little lost compared to annual gardening except periods of bare earth and weeding. These stages are generally the ones that support more wildlife and the forest garden is full of bees, beetles and birds.

Welsh onion (Allium fistulosum) is nothing to do with Wales: the name comes from wellisc meaning ‘foreign’ in Old English. It is also known as Japanese bunching onion, which is equally a misnomer as it’s thought to come from China or Siberia. Whatever it says on its passport though, it grows well in Britain and is a very useful allium.

There are two ways of harvesting it. It grows as a clump which slowly gets bigger, so you can lift and divide it, replanting half and using the other half as spring onions or scallions. This is how it’s mostly used in Asian and Jamaican cuisine. Alternatively, you can just pull green leaves off it almost all year round, except when it is flowering or in a hard winter when it dies down. Some people like the leaves chopped into salads but I find the flavour quite strong and only use it for cooking.

Welsh onions put a good deal of energy into producing quite chunky flowers, but this isn’t wasted as you can use the flower heads too. Pick them while they are still young and green and nip out the centre. You will have a shower of tiny flowers that you can use anywhere you would use chopped onion. (But leave a few for the bees.)