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Jeremy Bartlett's LET IT GROW blog

The wonder of plants and fungi.

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"People from a planet without flowers would think we must be mad with joy the whole time to have such things about us." - Iris Murdoch

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Saffron, Crocus sativus

Jeremy Bartlett's LET IT GROW blog Posted on 15 October, 2018 by Jeremy Bartlett4 March, 2021
Saffron, Crocus sativus

Saffron, Crocus sativus, with visiting Common Carder Bee, Bombus pascuorum. 8th October 2018.

It’s Saffron season on the allotment, though my ten plants won’t make me a fortune anytime soon.

Saffron, Crocus sativus, is a member of the Iris family, the Iridaceae. There are around 90 species of Crocus, and they are perennial plants that grow from a corm, a short, vertical, swollen underground stem. Crocuses flower in spring, autumn or winter and become dormant in the hot, dry summer months.

We often grow spring-flowering crocuses in our gardens, but Saffron flowers in autumn, as does its relative the very poisonous Autumn Crocus, Colchicum autumnale.

In Britain, Saffron’s leaves start to appear in very late September or early October, barely breaking the soil surface, then the flowers rapidly spring up and open, almost overnight, like fungi. The beautiful purple flower opens to reveal three deep orange female flower parts (styles and stigmas) and three lighter orange-yellow male parts (the stamens). It is the female parts (known as threads) which form the saffron strands we use in cooking. They are picked by hand, even in commercial cultivation. I gently pluck them by hand from my Saffron flowers, leaving the flowers intact. Tweezers are useful but you have to remember to take them with you. On a larger scale, it is easier to pick the whole flowers and take them home to remove the threads. Fresh saffron has no taste, and must be dried and left for about a month before it is used, after which it will keep for at least a couple of years in an airtight container.

Saffron is a very expensive spice, which is not surprising. About 150 flowers are needed to make one gram of dried saffron. (This estimate would require 68,000 flowers to make a pound of saffron; other estimates give 75,000 or even 80,000 flowers to the pound.)

It is hardly surprising that adulteration of saffron can be a problem. In extreme cases, horse hairs, corn silks and shredded paper have been substituted for the genuine article and last year the BBC reported that the synthetic food colourings tartrazine and sunset yellow were used in counterfeit powdered saffron. Marigold petals and Safflower (Carthamus tinctorius) have also been used as adulterants. Even adding the Saffron stamens to real Saffron will dilute the flavour.

We tend to think of Saffron as an exotic spice and much of what we use is imported from Iran (with about 90% of world production), Spain, Portugal, France and India. However, it will grow in some parts of the British Isles. The town of Saffron Walden was a centre of Saffron growing in the sixteenth to seventeenth centuries, before demand fell and the town became a centre for producing malt and barley. Earlier than that, Saffron was probably introduced by the Romans, then died out and was reintroduced around the fourteenth century [note 1]. Nowadays a quick search of the internet reveals that Saffron is grown in several places in Britain, including Norfolk (near Burnham Market), Cheshire, Essex (not far from Saffron Walden) and Devon.

If you want to grow your own saffron, you will need a sunny site with light but fertile soil. Our allotment has sandy soil which, with the addition of some organic matter – I use horse manure – suits the plant well. I did water my plants once this year in late September because it had been very dry, but this often isn’t necessary. The plants are hardy down to -26C but only if the soil is light.

Plant the corms 10 to 15cm (2 – 3 inches) deep and leave a 10cm gap between them. Keep the ground weed free, especially from September onwards. In my second year of growing I have so far found Saffron to be free of pests, but the Saffron Bulbs website lists a few potential problems, as well as giving lots of growing advice. Moving the corms every three or four years (when the plants are dormant) should prevent trouble, after which Saffron Bulbs recommends not using the same area again for ten years.

After flowering the leaves will continue to expand and will stay green through the winter, supplying food to the corm until they wither and disappear in May. Each year, the corms will multiply and already I have some that have doubled up and are producing two flowers. I planted my corms in early September 2017 and had three flowers in the third week of October. This year I have had fourteen flowers from seven plants, from early October, with more on the way. I recommend growing the plant for its beautiful blooms as much as the edible saffron threads. Late season bees and hoverflies seem to like them too: the aroma of fresh flowers in the sunshine is very noticeable even to the human nose.

As well as its use as an ingredient in cooking, Saffron has a number of actual and alleged medical uses. Most promising effects are on the treatment of Alzheimer’s disease, depression, menstrual discomfort and premenstrual syndrome. Sadly, Saffron may not be effective in treating asthma, psoriasis, cancer, stomach gas or baldness. It can also be used as a dye for cloth. However, as it is such an expensive spice, the Plants For A Future website notes that “it is little used at present because cheaper and more effective herbs are available”. The Science Direct website has details of some of the research that has been carried out on the plant and its effects. Active ingredients include picrocrocin and safranal, which give the taste and smell, and crocin, a carotenoid pigment that gives its colour.

Saffron can apparently “provoke laughter and merriment”, which could be useful, but Tournefort’s Herbal [note 1] warns that an overdose may cause people to die of laughing [note 2]. “A lady of Trent… almost shaken to pieces with laughing immoderately for a space of three hours, which was occasioned by her taking too much saffron“. (The WebMD website recommends that you avoid Saffron if you are bipolar.) Large doses of Saffron can cause poisoning and symptoms include  yellow appearance of the skin, eyes, and mucous membranes. More serious are vomiting, dizziness, numbness and bloody diarrhoea and bleeding from the nose, lips, and eyelids. Doses of 12 – 20 grammes can cause death.

The good news is that you’re not going to poison yourself if you use small quantities of Saffron, as in cooking. The BBC Good Food website suggests some recipes, as do the Allrecipes and Rawspicebar websites; a web search will find many more. One of my favourites is Nadine Abensur’s Carrots Braised with Cumin, Saffron and Garlic, which I originally found in my 2004 edition of “The Cranks Bible” – it is a lovely way of honouring home grown, organic carrots and saffron.

Humans have been cultivating Saffron for more than 3,500 years and cultivation probably began in Persia (modern day Iran). The plant is triploid and can only be grown vegetatively. It is not known in the wild but it probably originated from one or more wild Mediterranean species of Crocus, such as Crocus cartwrightianus (from Crete and Greece), Crocus thomasii or Crocus palasii.

Saffron, Crocus sativus

Saffron, Crocus sativus, on the allotment

23/10/2018: Stephen Barstow tells me that, in Palestine, the leaves of Saffron have traditionally been added to food as a condiment. Bulbs of several other species of Crocus have also been eaten (often roasted) in Turkey, Spain, Portugal, Italy and Palestine.

Notes

  1. J.P. de Tournefort, “The Complete Herbal, or the Botanical Institutions of Mr. Tournefort” (1719 – 30). Referenced in “Flowers and their Histories” by Alice M. Coats, published by Adam & Charles Black in 1956.
  2. This reminds me of the Monty Python sketch “The Funniest Joke In the World“, which you can watch on YouTube.
Posted in Edible, General, Ornamental, Poisonous | Tagged Crocus sativus, Saffron

Sand Dune Fungi

Jeremy Bartlett's LET IT GROW blog Posted on 6 October, 2018 by Jeremy Bartlett20 July, 2021

(With updates April 2020.)

At the end of September Vanna and I visited Holkham in North Norfolk to look for some of the specialist sand dune fungi that grow there.

Our friend Sarah, who took me to see Sticky Nightshade a few years ago, kindly gave us and our friend Ian a lift. When we arrived we met up with two of Sarah’s friends, Phil and Jane. Phil has a lovely photography blog, which now features some of the fungi we saw.

It has been a dry autumn so far in Norfolk and our first impression was that fungi were much less plentiful than at the same time last year. However, we managed to see an interesting selection, as well as a few flowers and insects. The soundtrack of the day was wind blowing the Marram Grass and the call of Pink-footed Geese – autumn had definitely arrived.

Here are some of the specialist sand dune fungi:

Dune Cup, Peziza ammophila

Our most impressive find was Dune Cup, Peziza ammophila. This cup fungus can be found amongst the sparse growth of Marram Grass (Ammophila arenaria) in consolidated areas of sand dunes. It develops underground and forms a deep cup- or urn-shaped structure, often mostly covered by sand. By blowing onto the cup, sand triggers the discharge of ripe spores, which are blown to new sites on the dunes. The fungus is a saphrophyte – it lives on dead and decaying organic matter. It is not considered to be edible.

Dune Cup, Peziza ammophila

Dune Cup, Peziza ammophila

Partly buried in the sand, the Dune Cup looks rather like a tiny moon crater and we half expected to see Clangers nearby. The Dutch name for the fungus is Zandtulpjes – “sand tulip”. The name ammophila means “lover of sand”.

Dune Cup is restricted to coastal sand dunes in Britain. Dune Cups occur in coastal dune systems in other parts of Europe and North America, though it is thought that “Peziza ammophila” is actually a species complex.

Dune Waxcap, Hygrocybe conicoides

I am a great fan of Waxcaps, a group of colourful fungi with a cool, waxen texture and often greasy or shiny caps, which I wrote about back in 2013.

Dune Waxcap, Hygrocybe conicoides, is a dune specialist, and grows in the grassier, more consolidated parts of dunes. Its name “conicoides” refers to its resemblance to Hygrocybe conica, the Blackening Waxcap, when young. However, the Dune Waxcap only blackens slightly, just on its stem, unlike H. conica.

Dune Waxcap, Hygrocybe conicoides

Dune Waxcap, Hygrocybe conicoides

The Dune Waxcap can also be found in coastal areas of Scandinavia, Germany, Spain and the eastern United States and Canada. It is thought to have been introduced to Hawaii.

Tiny Earthstar, Geastrum minimum

The Tiny Earthstar, Geastrum minimum, is indeed very small. It is exquisite and also rather rare, restricted to sand dunes at Holkham in Norfolk and Sandscale Haws and Drigg in Cumbria, although it is reported to be widespread in Europe.

There are about a dozen species of Earthstars (Geastrum) in Britain, named because they have a central spore sac, surrounded by rays that project outwards, giving the appearance of a star. The spores are dispersed when a raindrop hits the spore sac, or when a breeze blows across it.

The Collared Earthstar, Geastrum triplex, our largest species, has rays that are 5 – 11cm across when open. In contrast, the rays on a Tiny Earthstar are just 1.5 – 3cm across.

Tiny Earthstar, Geastrum minimum

Tiny Earthstar, Geastrum minimum

The Dwarf Earthstar, Geastrum schmidelii, is a similar size and is also found at Holkham. We saw some in 2017 but not this year. This guide from Kew Gardens includes a useful comparison of the two species. The most obvious difference is that the Dwarf Earthstar has a pleated pore opening.

Dwarf Earthstar, Geastrum schmidelii

Dwarf Earthstar, Geastrum schmidelii

Agaricus devoniensis

Agaricus devoniensis is another sand dune specialist, though it can occasionally be found on sandy soil away from the coast. Like other sand dune fungi, it survives in inhospitable surroundings by feeding on dead and decaying organic matter amongst the sand. It has whitish flesh but flushes pink when bruised. The smell is “mushroomy”.

Agaricus devoniensis is a relative of the cultivated mushroom, Agaricus bisporus. but I wouldn’t eat it because it is quite rare and also because “it is as edible as any nice meal topped with a liberal sprinkling of sand… you simply have to grit your teeth and get on with it“.

Dune Roundhead, Stropharia halophila

I thought the photograph below (taken on a previous trip to Holkham on 30th September 2017) was Agaricus devoniensis, but it turns out to be Dune Roundhead, Stropharia halophila.

I had no inkling of this until I was contacted in early April 2020 by Marco Contu from Sardinia. He has studied sand dune fungi for many years and he pointed out my error.  I checked with other members of Norfolk Fungus Study Group and they confirmed Marco’s identification.

Agaricus devoniensis

Stropharia halophila (Originally misidentified as Agaricus devoniensis.)

It turns out that Stropharia halophila is a pretty rare fungus. It was described as a new species in 1988, from Southern Italy.

The NBN Atlas shows just one record for the UK, from Ainsdale in Lancashire, but the species has already been seen in Norfolk: Penny David (the wife of dune fungus expert Maurice Rotheroe) found it at Holkham in 1992 and her record was confirmed by Thomas Laessoe.

Stropharia halophila is being assessed for the Global Red List of fungi. It has been recorded “from very few, scattered and fragmented localities” in France, the British Isles, Italy and the Netherlands. The fungus is thought to be saprotrophic on the litter of Marram Grass, Ammophila arenaria.

Sand Stinkhorn, Phallus hadriani

We looked in vain for another sand dune specialist, Sand Stinkhorn, Phallus hadriani (also known as Dune Stinkhorn). This is a relative of the common and very smelly Stinkhorn, Phallus impudicus, which is found (and more often smelt) in woodland during the summer months.

Both species have the same phallic appearance, but Phallus hadriani is smaller and the “egg” from which the fruit body grows is pinkish-lilac, rather than white.

I’m used to the rotting flesh smell of the Stinkhorn so when I found a specimen of Sand Stinkhorn at Holkham last September I was pleasantly surprised by the much more delicate, slightly perfumed odour. Not everyone is as lucky – while I agree with the descriptions of the smell as “faint and pleasant” and “like violets”, some people think it is “fetid or putrid”. (More recently I have found some more mature specimens and they are a lot smellier, though not in the same league as Phallus impudicus.)

Dune Stinkhorn, Phallus hadriani

Sand Stinkhorn, Phallus hadriani

Outside the British Isles, Phallus hadriani has been introduced to Australia on woodchip and in North America it grows on decomposing tree stumps and roots.  In Poland it forms a symbiosis with xerophilous grasses and the Black Locust tree, Robinia pseudoacacia.

The specific name hadriani is named after the Dutch botanist Hadrianus Junius (1512–1575). Also known as Adriaen de Jonghe, he was the author of a 1564 pamphlet on Stinkhorn fungi.

(We returned to Holkham dunes in autumn 2019, when sand Stinkhorn was present in good numbers. Fungi are like that – every year is different, which is part of the joys of looking for them.)

Sand Stinkhorn, Phallus hadriani

The pinkish lilac egg of Sand Stinkhorn, Phallus hadriani

 


References

There is not that much information on the internet about these fungi, compared to some of the subjects I have written about, so I have relied heavily on the First Nature website for much of the information here. Other sources include Wikipedia and the excellent book “Collins Complete Guide to British Mushrooms & Toadstools” by Paul Sterry and Barry Hughes (Harper Collins 2009), where specialist sand dune fungi are described on page 340. Thanks to members of Norfolk Fungus Study Group and Marco Contu for their help with Stropharia halophila.

Posted in Fungi, General | Tagged Agaricus devoniensis, Dune Cup, Dune Waxcap, Geastrum minimum, Holkham, Hygrocybe conicoides, Peziza ammophila, Phallus hadriani, sand dune fungi, Sand Stinkhorn, Stropharia halophila, Tiny Earthstar

Bindweed Rust, Puccinia convolvuli

Jeremy Bartlett's LET IT GROW blog Posted on 20 September, 2018 by Jeremy Bartlett6 October, 2018
Puccinia convolvuli

Bindweed Rust, Puccinia convolvuli. View of the fungus on the upper surface of Hedge Bindweed leaves (Calystegia sepium).

Bindweed Rust, Puccinia convolvuli

Bindweed Rust, Puccinia convolvuli. View of the fungus on the underside of Hedge Bindweed leaves (Calystegia sepium).

A week ago (11th September 2018) Vanna and I took the train to Woodbridge in Suffolk. It’s a lovely place to visit, with interesting old buildings, good pubs and independent shops and walks beside the River Deben. We visited the churchyard of St. Mary’s Church, to see a large and impressive nesting aggregation of Ivy Bees (Colletes hederae). There were masses of male bees flying low over the ground, looking for females emerging from nest holes. Each female was surrounded by a cluster of male bees, forming a mating ball, in which one lucky male was able to mate. A few females had already mated and were digging out their nest holes or flying off to nearby Ivy to collect pollen and nectar. We chatted with several visitors, who had seen us taking photographs and read printed signs thoughtfully put there to explain what the bees were doing.

After a pub lunch we walked down a footpath next to an Ivy covered hedge, on the hunt for more bees to photograph, but we were soon distracted. Near the start of the path there was a big patch of Hedge Bindweed, Calystegia sepium, and Vanna noticed that many of the leaves were covered in orange-brown pimples. On closer inspection these appeared to be some sort of rust, which we didn’t think we’d seen before.

When we came home I did an online search and found out from the excellent Plant Parasites of Europe website that the fungus was probably Puccinia convolvuli. Vanna also posted photos on Facebook, on the British Plant Galls site, and Malcolm Storey confirmed the identity of the fungus. Previous records in the UK have been of only a few pustules per leaf, rather than whole leaves covered in them.

Puccinia convolvuli has only recently been discovered in Britain and there have only been a handful of records so far, the first from near Weymouth in Dorset in 2009. I sent the details of our find to the Suffolk Fungi Recorder, Neil Mahler, and he confirmed that our sighting was the first record for Suffolk. Since we came home we’ve been looking at Hedge Bindweed here in Norwich, but haven’t seen any infected plants here yet.

Further afield, Puccinia convolvuli occurs in other parts of Europe and in Asia and North America. It will also infect other species of bindweed, including Mallow Bindweed (Convolvulus althaeoides), Field Bindweed (Convolvulus arvensis) and California Rose (Convolvulus japonicus, now known as Calystegia japonica).

Although Hedge Bindweed (Calystegia sepium) has lovely flowers, it is often a troublesome weed, as it grows very vigorously and has deep roots that are hard to dig out. As Puccinia convolvuli can cause extensive damage to the plant, it is not surprising it has been studied as a possible biological control of Hedge Bindweed. In his 1992 Masters thesis Jonathan Beener of Eastern Illinois University concluded that further investigation was worthwhile. (Beener, Jonathan C., “Evaluation of Puccinia convolvuli (Pers.) Cast. as a Biological Control of Calystegia sepium (L.) R. Br.” (1992). Masters Theses. 2118.). There have also been several studies biological control of bindweeds by another fungus, Phomopsis convolvulus, such as in the journal Weed Science (Morin, L., Watson, A., & Reeleder, R. (1989). Efficacy of Phomopsis convolvulus for Control of Field Bindweed (Convolvulus arvensis). Weed Science, 37(6), 830-835.)

Both Jonathan Beener’s thesis and the Phrygana website state that Puccinia convolvuli prefers growing in more humid places. This means that  growth of the fungus is restricted in more open situations (such as fields), which could limit its use as a biological control. It will be interesting to see how the fungus spreads throughout the British Isles, and whether it does better in wetter western areas.

Worldwide, Puccinia convolvuli is not the only rust that grows on bindweed. In 2003 a related species of Puccinia was identified in Japan, Puccinia calystegiae-soldanellae, growing on Sea Bindweed, Calystegia soldanella (Zhuang Li, Teruo Sano, Takashi Fujita, Fusaka Nakai, Yukio Harada (2004). Puccinia calystegiae-soldanellae, a new rust species on Calystegia soldanella from Japan. Mycoscience, 45 (3),Volume 45, Issue 3, pp200 – 205.)

When you go for a walk, keep an eye open for infected bindweed leaves and, if you find any infected with Puccinia, send a record (with photos) to your local fungi recorder. To help you, you can compare specimens with the excellent photographs of Puccinia convolvuli on the Plant Parasites of Europe website, Bioimages and Phrygana websites.

The photos on this page are by Vanna Bartlett.

Posted in Fungi | Tagged Bindweed Rust, Puccinia convolvuli, Woodbridge

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