Chilean Nasturtium, Tropaeolum tricolor

Tropaeolum tricolor

The Christmas Box that I wrote about last month has finished flowering but mild spring weather has brought more plants into flower in our garden, including Primroses, Lungwort, Mirabelle Plums, Perennial Wallflowers, Chocolate Vine, Daffodils, Mediterranean Spurges and Lesser Celandines.

Indoors, the current star attraction is the Chilean Nasturtium, Tropaeolum tricolor, in our north-facing conservatory. Also known as Three-coloured Indian Cress, it is a beautiful perennial climber, which grows from small tubers. In summer the plant is completely dormant but in late autumn (usually November), thin wiry shoots start to appear and gradually start to climb up any support, often reaching out to embrace nearby house plants. If kept frost free, the plant starts to flower in mid March and more and more lovely flowers are produced until mid or late May, when the whole plant starts to die back, before disappearing below ground by June. I use a good quality peat-free compost to grow my Tropaeolum tricolor, such as New Horizon or Fertile Fibre, and I keep the compost in the pot slightly moist during the growing season, then allow it to dry out completely during the summer.

Tropaeolum tricolor can grow to 3 – 3.6 metres (9 – 12 feet) tall if it is allowed to climb high enough. My plant grows to about 1.5 metres (just under five feet) tall, but that is because my plant supports are that height, and next year I plan to use taller supports.

The Chilean Nasturtium’s leaves are bright green, lobed and peltate – that is, the leaf stalk connects to the middle of the leaf. The flowers grow singly on long wiry stalks arising from the leaf axils. Each flower is about three centimetres (1.2 inches) long and the majority of the flower consists of its five reddish-orange sepals tipped with a purple band, extending backwards in a red spur. In contrast, the petals are small and greenish-yellow, but the overall effect is lovely and the three different colours give the plant its name of “tricolor“. The Strange Wonderful Things website says that the flowers “swim like schools of tropical fish throughout winter”, which I think is a lovely and very apt description.

Although it is sometimes called the Bolivian Nasturtium, the name Chilean Nasturtium is more appropriate as Tropaeolum tricolor is a native of Chile, where it grows in cloud forest, 300 to 900 metres (980 to 2,950 feet) above sea level. Further south, it will grow at lower levels in temperate forests. Here it can endure up to 10 months of drought in the summer, when it is dormant. It is generally classed as half hardy, tolerating cool conditions down to about freezing point and the RHS gives it a hardiness rating of H2. The USDA hardiness zone is 8. In its native habitat, well buried tunbers are hardy to – 8 Celsius, and this year I found a plant growing (albeit slowly) in a pot outdoors in the garden, where temperatures had reached – 3 Celsius or lower at night.

In Chile, the flowers are pollinated by a hummingbird, the Green-backed Firecrown, Sephanoides sephaniodes. But not in Norwich – I will just have to listen to their call and use my imagination when I look at the plant.

Tropaeolum tricolor can be grown from seed, but this is said to be quite tricky. It is easier to grow the plant from a tuber and I bought mine from Hethersett Plant Fair a couple of years ago. (The fairs are organised by Norfolk Plant Heritage twice a year, and are well worth a visit). Every year, new tubers are formed, so you should have a gradually increasing stock of plants. If you have any spares, you can always eat them.

The genus Tropaeolum (family Tropaeolaceae) also contains the better known Nasturtium, Tropaeolum majus, as well as the beautiful Canary Creeper, Tropaeolum peregrinum and, my favourite, Tropaeolum speciosum, known as the Scottish Flame Flower. This appreciates damp, acidic soil and it likes growing up hedges in Scottish gardens, where its fiery red flowers contrast with dark evergreen Yew foliage.

Tropaeolum tricolor

Christmas Box, Sarcococca hookeriana

Sarcococca hookeriana 'Winter Gem'

Sarcococca hookeriana ‘Winter Gem’

Winter flowers are very precious and scented winter flowers are doubly so. I’ve already written about Winter Heliotrope, a winter Honeysuckle, Witch Hazel and Viburnum bodnantense. Christmas Box, Sarcococca hookeriana, is another of these lovely winter pick-me-ups.

Christmas Box, also known as Sweet Box, is a compact, evergreen shrub. Its leaves are more pointed than true Box (Buxus sempervirens), though both are in the same family, the Buxaceae.

Several varieties of Sarcococca are grown in gardens. These include three natives of China: Sarcococca hookeriana var. humilis, which grows to 60cm tall, the larger Sarcococca hookeriana var. digyna (to 1.5 metres tall) and Sarcocococca confusa, bigger still (up to 2 metres tall). S. hookeriana spreads slowly by suckers but these appear close to the plant, so aren’t a nuisance; S. confusa doesn’t produce suckers. After flowering, S. hookeriana and S. confusa bear attractive glossy black berries.Their close relative Sarcococca ruscifolia has red berries.

The variety of Christmas Box that I grow is Sarcococca hookeriana ‘Winter Gem’, which will reach about 60cm tall after about six years. It is a hybrid between S. hookeriana var. digyna ‘Purple Stem’ and S. hookeriana var. humilis.  In my north-facing garden in Norwich it flowers in February. On a warm day (like early last week) the smell of the flowers drifts several feet away from the plant but when the weather is cold you may need to cup your hands around the flowers and breathe on them to release the scent, as with Witch Hazel. I would describe the perfume as  a spicy honey, less sweet than Winter Heliotrope and most similar to Witch Hazel.

Christmas Box are reliable and easy to grow. They are happy in full or partial shade in a variety of soils and our plant copes well in our sandy soil in semi-shade. (I added garden compost when I planted it just over two years ago.) Unlike the true Box, they aren’t affected by the dreaded Box Blight.

Scarlet Elfcup, Sarcoscypha austriaca / Ruby Elfcup, Sarcoscypha coccinea

Scarlet or Ruby Elfcup

“Oh good”, I thought. “A nice and easy fungus to identify.”

We were walking through the woods at Strumpshaw Fen RSPB Reserve on Tuesday when we spotted a beautiful red cup fungus, growing on pieces of dead, moss covered Rhododendron wood.

I was pretty certain that this was the Scarlet Elfcup, Sarcoscypha austriaca, and I thought I’d confirmed this when I consulted my copy of “Collins Complete Guide To British Mushrooms & Toadstools” by Paul Sterry and Barry Hughes (one of the best general fungi identification guides at the moment).

It was only when I looked on the internet when researching this blog post that I found out that, as so often with fungi, life isn’t quite so simple. As well as the Scarlet Elfcup, Sarcoscypha austriaca, there is the Ruby Elfcup, Sarcoscypha coccinea. Both species can be found on dead logs and twigs in damp, shady places, usually partly buried in moss. They can be found from early winter into early spring: a real treat to discover when various shades of brown are the norm.

In the species accounts on the First Nature website, Pat O’Reilly describes the two species as “macroscopically almost identical”. The colour of both species can vary from pale orange to deep red and although Scarlet Elfcups are sometimes bigger than Ruby Elfcups, there is a great deal of overlap in size, so neither of these characteristics is a reliable way to separate the two species. But help is at hand

If I had examined the outer surface of the cups, I might have been able to tell which Elfcup I had found. The Ruby Elfcup (S. coccinea) is covered in a matted felt of tiny uncoiled hairs, while the Scarlet Elfcup (S. austriaca) has hairs that are coiled, rather like a corkscrew. Under a microscope, the spores of both species are elongated ellipsoids but some of the spores of the Ruby Elfcup (S. coccinea) have a hammerhead appearance at the ends (the conidial buds). As with many groups of fungi, DNA sequencing has been used in recent years to reveal previously unknown relationships between members of the genus Sarcoscypha [see note 1, below]. 

Elfcups are Ascomycete fungi – part of the family Sarcoscyphaceae in the Order Pezizales, the Cup Fungi. Other well-known Cup Fungi include the Orange Peel Fungus, Aleuria aurantia, which grows on disturbed ground and bears an uncanny resemblance to a piece of discarded orange peel.

Both the Scarlet Elfcup and Ruby Elfcup are generally reckoned to be edible, though they must be cooked first. I haven’t tried them (and, if they are growing in a nature reserve, neither should you).

WildFoodUK describes the taste as “mild, mushroomy”, which is only a faint recommendation, but the colour would add drama to the plate. There are several recipes on the internet, including Roast turbot with garlic shoots and scarlet elf cups, Fillet of sea bass with scarlet elf cup, wild garlic and spring herbs and Elf Cups Stuffed with Egg and Three Cornered Leek. (All three use other seasonal ingredients and use either Wild Garlic or Three-cornered Leek to give a bit of Allium flavour.)

The colour of Elfcups is due to five different carotenoid pigments, including betacarotene (also found in carrots and many plants) and plectaniaxanthin. It is the latter compound that is mainly responsible for the red colour.

Elfcups have sometimes been used to make table decorations. The fungus was also used as a traditional medicine by Native Americans, ground up into a powder and used as a styptic to heal the navels of unborn children.

Or you can just leave them where they are, to brighten up woodland and bring cheer to the darkest months of the year.


Note 1 – See, for example, “Relationships among Sarcoscypha Species: Evidence from Molecular and Morphological Characters” (Francis A. Harrington, Mycologia Vol. 90, No. 2 (Mar. – Apr., 1998), pp. 235-243) and “Phylogenetic Relationships within Sarcoscypha Based upon Nucleotide Sequences of the Internal Transcribed Spacer of Nuclear Ribosomal DNA” (Francis A. Harrington and Daniel Potter, Mycologia Vol. 89, No. 2 (Mar. – Apr., 1997), pp. 258-267).

Corncockle, Agrostemma githago

Corncockle, Agrostemma githago

Our annual wild flower patch, including Corncockle (left and centre: pinky-purple flowers)

Corncockle, Agrostemma githago, is one of my favourite wild flowers. We grow it in the garden, in our annual wild flower patch and at the allotment. It’s also suitable for growing in a pot with other cornfield annuals.

Corncockle is a hardy annual in the Carnation family, the Caryophyllaceae, whose members include carnations and pinks (Dianthus), campions, catchflies (Lychnis) and Chickweeds (Stellaria). It has an upright growth habit with long, narrow and softly hairy leaves and single pinky-purple flowers from June until August. These are followed by a seed capsule full of heavy, black seeds. These are very easy to collect in late summer, to sow elsewhere, or you can leave them to fall. They tend to stay around the site of the original plant, meaning you can have a patch of Corncockle in the same place year after year. You can simply let seed drop onto the soil, or give it a bit more care, as described in this article: “Grow Corncockle From Seed” Ideally, sow the seed in spring.

Corncockle

Corncockle flower

Corncockle was once common in wheat fields and is thought to have been introduced into Britain from Southern Europe along with crops, in the Iron Age. It is one of a number of plants introduced long ago, known as archaeophytes. (If you want to read more, I recommend “Alien Plants” by Stace and Crawley, 2015, one of the New Naturalist series. A complete list of British archeophytes is in Appendix 2.) Corncockle occurs as a weed in the United States but in the British Isles it is extinct as an agricultural weed, where it has been reintroduced in wild flower seed mixtures.

You can buy Corncockle seeds on their own from Emorsgate Seeds and they are often available in annual wild flower mixes, such as the free packets of seeds supplied by Kew Gardens’ Grow Wild project for several years. We planted this seed mix in Wensum View Park in Norwich a couple of years ago, where it made a very pretty display.

Corncockle seeds and leaves are poisonous but as writer John Robertson puts it: “It is only poisonous if you eat it and there’s absolutely nothing about the corncockle that’s going to encourage you to eat it.”

Corncockle contain a variety of compounds, including the saponins githagin and agrostemmic acid. However, these compounds are poorly absorbed by the body and most will pass through the gut without causing harm. The leaves can be cooked and eaten, according to the Plants For A Future website – thorough cooking, with a change of cooking water, is thought to remove most of the saponins. However, I haven’t tried eating Corncockle leaves and the Plants For A Future website describes them as “a famine food – used when all else fails“. The plant has several medicinal uses and is a diuretic, expectorant and vermifuge.

Until modern methods of farming and food preparation were developed, Corncockle seeds were difficult to separate from harvested grains and would have been eaten accidentally as a food contaminant. York Archaeological Trust has published a fascinating article about Corncockle, entitled ‘The COCKLE of Rebellion, Insolence, Sedition…’ – The Corncockle, by Allan Hall. This mentions that Corncockle seeds were found in excavations in York and in a late 13th / early 14th century cesspit in Chester, having passed through the human gut. The article records that Gerarde, the 17th Century herbalist, wrote “‘what hurt it (cockle) doth among come, the spoyle unto bread, as well as in colour, taste, and wholesomeness… is better knowne than desired’. The quote is also used in “The Running Hare: The Secret Life of Farmland“, by John Lewis-Stempel (Doubleday 2016). There is at least one known case of someone dying from eating bread contaminated with large quantities of Corncockle seed. However, mild poisoning was more likely, where symptoms included “nausea, belching, headache, dyspepsia, and unpleasant taste in the mouth, a tickle in the throat, hoarseness and coughing, with increased mucous secretion. Stronger doses led to dizziness, restlessness, delirium and eventually convulsions and injury to the circulatory system“.

Chickens can be affected if they eat Corncockle seed: they can “present a generally listless and unkempt appearance with rough feathering and diarrhea”, according to the United States Food & Drug Administration.  The Illinois Noxious / Invasive Species factsheet states that “The green parts of corn cockle contain so little poison that animals can browse them freely without showing any ill effects. But the seeds are so poisonous that any animal may die from eating ¼ to 1 pound ground cockle seed per 100 pounds of body weight.”

Corncockle seed and its potential use as a poison features in “The Accusers” by Lindsey Davis, which I have just finished reading.  It is one of twenty very entertaining books featuring Marcus Didius Falco, a laid-back Roman informer, set between 69 and 77AD.

Kew Gardens’ Grow Wild project is a “the UK’s biggest-ever wild flower campaign, bringing people together to transform local spaces with native, pollinator-friendly wild flowers and plants“. Communities are encouraged to grow our native wild flowers and, by doing so, provide homes and sustenance for insects such as solitary bees.

During 2014 the BBC’s “Countryfile” programme helped to publicise the excellent work being done by the Grow Wild project but The Telegraph, rather than give its blessing to this attempt to make our landscape more beautiful and diverse, decided to use corncockle (figuratively) as a club to hit the BBC: “Project promoted by BBC spreads poisonous wild flowers across Britain“. The Express did nothing to soothe nerves, with “Look but don’t touch! Pretty flower so poisonous that it could KILL returns to the UK” when the plant was found growing in the Sunderland area. “Residents are urged that if they do see the corncockle, they should not disturb it in any way“. In Wootton Bassett, Corncockle plants were fenced off and the flowers were cut to stop the plants from seeding.

If I believed what I read in certain newspapers, I would probably be wearing a biohazard suit by now. Fortunately  Patrick Barkham, writing in The Guardian, gave a much more balanced view, as did John Robertson on his The Poison Garden website.

I encourage you to grow this lovely plant and to beware of dubious news stories. The Finnish website NatureGate has some lovely photos of Corncockle, which amply demonstrate why you should grow what is sometimes called the “crown of the field“.

Ivy, Hedera helix

Happy New Year! Since we have a few days to go until Twelfth Night, there is time to shoehorn in a festive reference:

The holly and the ivy,
When they are both full grown,
Of all the trees that are in the wood,
The holly bears the crown.”

I do like Holly, Ilex aquifoilum, but I prefer Ivy, Hedera helix. And Ivy isn’t just for Christmas – it provides a year-round habitat and food source for wildlife.

Small Tortoiseshell on Ivy flowers

Small Tortoiseshell butterfly feeding on Ivy flowers

Ivy is an evergreen climber and is native to western, central and southern Europe but it has been introduced into Australia, New Zealand and the western United States. It is Britain’s only evergreen liana. It belongs to the family Araliaceae, a family of around 250 species found in the Americas, Eurasia, Africa, Australia, New Zealand, New Caledonia and Pacific islands. Other well-known members of the family include Ginseng, Panax quinquefolius, whose roots are used in herbal medicine, the British wild flower Marsh Pennywort, Hydrocotyle vulgaris (which was considered to be a member of the Umbelliferae when I did Botany), the widely grown ornamental shrub Fatsia japonica and the Rice-paper Plant, Tetrapanax papyrifer, which I wrote about in October 2013.

Six pages of Richard Mabey’s ‘Flora Britannica’ are devoted to Ivy. It has a rich folklore, some of which is documented by the Owlcation website. I like Ivy’s association with the sale of alcohol – in medieval times ivy-covered poles were used to advertise taverns. (This led to the expression “Good wine needs no bush“.) Goblets were sometimes made out of Ivy wood and Ivy berries were supposed to overcome the bad effects of alcohol, although trying this is not a good idea because the plant is mildly poisonous. The Plants For A Future website describes Ivy as a bitter aromatic herb with a nauseating taste, so possibly it is better to stick with that hangover.

Various other uses for Ivy include making a brown dye from the twigs, using the leaves to wash clothes or restore black fabrics and, under the supervision of a qualified practitioner, as a folk medicine. The last point is important, as Ivy leaves and berries contain a saponin known as hederagenin, which can cause breathing difficulties and coma if ingested in sufficient quantities. Ivy sap can also cause dermatitis with blistering and inflammation, possibly due to the presence of polyacetylene compounds.

Other English names for Ivy include Cat’s foot, Me Hoofe, Robin-run-in-the-edge, True Ivy and Tun-hoof. Our Ivy, Hedera helix, is not related to the American species known as Poison Ivy, Toxicodendron radicans (Eastern Poison Ivy) and the related Toxicodendron rydbergii (Western Poison Ivy).

As the tough stems of Ivy creep along the ground, they root into the soil at intervals and produce lovely deep green leaves with three to five lobes and contrasting pale veins. These are known as shade leaves and the plant produces them as it grows over the ground and then first starts to climb up trees or walls. This growth can be very dense and will smother out other plants which is why it is often planted in gardens as a groundcover plant and especially as it happily grows in dense shade and dry conditions on poor soils. There are many garden cultivars, with different leaf shapes and colours.

Ivy - shade leaves

Ivy – shade leaves

Once the Ivy has scrambled its way up a tree or building and is growing in full bright sunlight it will it produce what are known as sun leaves. These are a lighter shade of green with less prominent veins and are a pointed oval in shape. It is only when the plant has put on a good growth of these leaves that it will then produce its lovely delicate flowers. An interesting fact about Ivy is that if you cut a stem of sun leaves and root it, it will grow into a self supporting free standing Ivy Bush.

Ivy - sun leaves and berries

Ivy – sun leaves and berries

Ivy is a very divisive plant, loved by some but loathed by many – including some foresters and custodians of ruinous buildings. It has a reputation for strangling or smothering trees and is sometimes assumed to be parasitic, sucking the life out of its host tree. But this is untrue – Ivy makes all its own food through photosynthesis and has its own root system for drawing up water and nutrients from the soil.

Ivy uses trees and walls as a support to scramble up and it can eventually clothe an entire tree in an evergreen mantle. This can deprive the tree’s leaves of light and, on dry soils, Ivy’s roots will compete with the tree for available water. Eventually the lush growth of Ivy at the top of the tree can make it top-heavy and vulnerable in strong winds or heavy snow fall, when the extra weight can bring branches down or even topple the tree. Because of this, foresters will regularly hack through the thick stems of Ivy enveloping trees near their base, cutting out a foot or so and then leaving the whole lot on the tree to wither and die, leaving an unsightly mess.

Ivy on walls and buildings can sometimes do damage too, but it can also protect walls. As the Ivy scrambles up any structure, it clings to it with little rootlets coming off the main stems. When the rootlets find crevices in walls, the plant will then send out proper roots into the structure and as these grow they can split any cracks further open. Often the main problem with ivy on old walls is when you try and pull it off – it clings so tenaciously that you can end up pulling off bits of wall with it. Because of this, on many old ruins it is now left in place, indeed sometimes it is the Ivy that is actually holding the structure together and keeping it upright. In cemeteries Ivy will cover gravestones, making them unreadable and potentially damaging some memorials, so it is often removed before it puts on too much growth.

However, if Ivy is allowed to climb up a dead or moribund tree, it can extend its wildlife habitat value beyond the life of the tree. Dead and decaying trees are of supreme wildlife importance to a variety of rare and vulnerable creatures, from beetle and moth larvae to roosting bats and nesting birds. Unfortunately such trees often end up being felled as they can pose a threat to people and property when they eventually come down. There is also a tendency amongst some to constantly ‘tidy-up’ the countryside by removing ‘dangerous’ trees even in the middle of woods.

Provided Ivy is given the occasional trim, it is a very beneficial plant, as it forms a kind of high-rise hotel for wildlife. Being evergreen, it provides shelter for invertebrates all year round, nesting sites for birds in the spring and summer and food for much of the year.

On woodland floors and hedge banks, a thick covering of Ivy leaves will conceal the entrances to mice and vole holes as well as bumblebee nests. Higher up, on old walls, Wrens, Blackbirds, Robins, Thrushes and other birds will nest in its dense cover. Ivy’s dense evergreen foliage provides ideal places for hibernating insects to securely sit out the winter, including butterflies like the Small Tortoiseshell (pictured above), Brimstone and Comma, as well as hoverflies and ladybirds. In spring a big clump of Ivy in a sunny position is a good spot to to look for emerging hoverflies and ladybirds as they crawl out of the dense cover to warm themselves before flying off to forage.

Hole amongst Ivy

On woodland floors and hedge banks, a thick covering of Ivy leaves will conceal the entrances to mice and vole holes as well as bumblebee nests.

Ivy flowers in autumn are perhaps its greatest gift to wildlife. Ivy flowers are produced in small, dense umbels and are pale yellow-green in colour. They are produced in September and will carry on flowering through October and well into November. Ivy is one of our latest flowering native plants and is an extremely important source of nectar for honeybees, wasps, hoverflies and butterflies. The flowers have a distinctive scent – a heady smell of honey – and some beekeepers harvest Ivy flower honey from their hives. It has a very distinctive taste, which I personally find a bit too overpowering.

On a sunny autumn day Ivy flowers will be covered in honeybees, so much so that you can actually hear the hum of their wings. If you search amongst the honeybees you will hopefully find some hoverflies, usually Eristalis species (Drone Flies) which mimic the honeybee in coloration but also sometimes something a bit more exotic like Volucella zonaria, a very large migrant hoverfly that is a perfect hornet mimic.

Drone Fly on Ivy flowers

Drone Fly on Ivy flowers

Ivy flowers are also a magnet for wasps, including the males, with their long antennae. There were good numbers of wasps on Ivy flowers this autumn, but numbers have plummeted in the last few years. Although they can be a nuisance at picnics, wasps form a vital part of the web of life. They are important pollinators and pest controllers, collecting and killing numerous caterpillars, whitefly and other nuisances to the kitchen gardener.

Another beneficiary of Ivy’s rich nectar is the Red Admiral butterfly which can often be found feasting on the flowers. In milder winters the butterfly may well hibernate in the dense leaves but they can be killed off by heavy frosts and long cold spells.

Red Admiral butterfly

Red Admiral butterfly on Ivy flowers

Holly Blue butterflies lay their eggs on the infant buds of the Ivy, their caterpillars feeding on them as they develop. Once the flowers are pollinated, the small green berries start to swell, turning brown and then ripening a lovely deep blue-black. These will persist right through the winter, surviving frosts and snow. They are beloved of Wood Pigeons and are a saviour to Blackbirds and Thrushes as well as overwintering Blackcaps.

When I wrote about Sea Aster last month, I mentioned the Sea Aster Bee, Colletes halophilus. Since 2001 the related Ivy Bee, Colletes hederae, has been spreading northwards in the British Isles. It reached Norfolk in 2014 and by the end of last year it had reached North Yorkshire and Lancashire. It is a very distinctive species, emerging late in the summer ready to feed on Ivy flowers. We found it in several parts of North Norfolk in our week staying at Wells-next-the-Sea, and there is a large colony on the outskirts of Costessey, only a few miles away from home. It is likely to continue its spread in 2017, so keep a look out on Ivy flowers this autumn.

Ivy Bee, Colletes hederae, on Ivy flowers

Ivy Bee, Colletes hederae, on Ivy flowers

Some plants benefit directly from Ivy too. Ivy Broomrape, which I wrote about in June 2016, is a parasite that grows on Ivy.