Peter Coles talks to Dr John Feltwell, botanist, ecologist,  founder of Wildlife Matters, photographer and intrepid explorer. He is author of the definitive book on silk, The Story of Silk.

How did you first come to be interested in silk — and mulberries?

Having been raised on Ashdown Forest in East Sussex I was always interested in butterflies. I was forever ferreting around in forest ditches. I am told that, as a very young boy, I used to sleep in my wellington boots. Years later, it was only natural for me to choose the cabbage white butterfly as the subject for my PhD thesis -- it was common, and still is common, occurring from here right through to China. In recent years it has even got itself through border control in New Zealand, and I have been down there to assist its control (all credit to a resourceful butterfly with over 100 food plants, including cabbage).  

Most butterfly and moth caterpillars produce silk in their caterpillar stage, which they use to hang on to leaves, to follow each other, keep in touch and to string themselves as pupae or chrysalids on stems, and to enclose themselves in cocoons. The silk moth is no exception. However, the exception with the silk moth is that it has been domesticated for so many millennia that it cannot fly, so the silk moth does not go anywhere when it hatches from the cocoon. It has wings but they are stubby. They mate on their cocoons.

The caterpillars that hatch from the eggs are lugubrious and do not wander around like other caterpillars; they are just voracious ‘chompers’ of mulberry leaves. Pretty much any mulberry species will do, so long as it is mulberry, the Morus genus.

My interest in silk and mulberries (they naturally go together) was stimulated when I became involved with the restoration of a farmhouse in the Cévennes region of France, which had been used for raising silkworms in the 18^th century. At the time, this was the farmer’s main source of income – a six-week period of intense activity. During the restoration, old silk cocoons would fall out of the wall where lost caterpillars had pupated a hundred or so years ago. My interest in the silk moth was sealed and my book on silk[1] was another ‘opus’ thesis.  And yes I like mulberries, a very underestimated fruit, with a sweet, fruity punch.

In your book, The Story of Silk, which came out in 1990, you spend some time talking about the French silk farms and silkworm houses (magnaneries), like the one you restored in the Cévennes. Which mulberry trees were grown?  Are any still there today?

Magnaneries were rooms where silkworms were raised, they were not usually separate buildings, but they could be wood sheds or attics or rooms where once sweet chestnuts were roasted to shed their skins (rooms called cledes in the Cévennes). In some cases rooms were added onto the sides of existing houses, or extra storeys were added. Every room was furnished with a wood fire in each corner simply to keep the caterpillars warm and stop them getting chilled. The Cévennes is a mountainous region and cold springs could kill caterpillars.

This was an industry that ran throughout the south of France, from Lyons southwards and across the north of Italy. When the postman delivered a batch of silkworm eggs, the Madame of the household would keep them safely incubated in a pouch on her bosom. This meant that most of the income of the household was entrusted to Madam’s bosom, so she had to be careful!

As the caterpillars hatched, they would be put onto fresh mulberry leaves and would immediately start eating. The noise made by thousands of munching caterpillars could sound like falling rain. The leaves were laid out in each room on big beds made of split cane. Each room would have perhaps 6-8 beds from floor to roof, the beds being open with no sides or cover as the caterpillars do not go anywhere. There would be a narrow row down the middle of the room between the tiers of beds, so that they could be supplied with mulberry leaves. 

The white mulberry (Morus alba) was used exclusively across the Mediterranean for raising silkworms. No other mulberry species would do, and other non-mulberry species were tried out, with no real success.  As the local economy was based on raising silkworms, the abundance of white mulberry trees shaped the landscape of the towns, villages and hamlets. The trees were pollarded, so that each year the long wands of leaves were cut off and taken to the hamlets for the silkworms. Pollarding  -- cutting the stems off above the height at which goats could graze -- meant that the top of the trunk swelled up at the end of each season, giving the trees a characteristic appearance. This can be seen today, where many pollarded white mulberries are still to be found on terraces and around hamlets.

What were conditions like for the workers in a silk farm?

In France, at least in the Cévennes mountains, there were no ‘farms’ as such; it was more like a cottage industry carried out by tens of thousands of households. Once the silk cocoons were produced they were sold into a co-operative which had spinning mills where the silk was drawn out from the cocoons. This was carried out in large buildings set up beside rivers where the industrial machinery was powered by water dammed in sluices. It was hard work, mostly carried out by women and children, who worked long hours away from home. Having interviewed one silk worker, I gather it was not a job that they would like to do again -- not least having sore hands from teasing out the silk from the hot cocoons that were boiled to loosen the fibres.

You tracked down England’s only successful (20^th century) silk farm, Lullingstone, which is now closed, in search of the mulberry trees. Did you find any?

White mulberry trees were grown, especially at Lullingstone Castle in Kent by Lady Zoë Hart Dyke, and, with her helpers, she gathered leaves from other mulberry trees locally. Sadly, all of these trees have been grubbed out. The new custodian of the Castle, Tom Hart Dyke has now created a World Garden of Plants that celebrates a wider collection of flora.

Your book Black and White In the Wild is just about to come out. What is it about?

About black and white animals in the wild, including albinos and melanic forms. There is even a black and white variety of silk moth caterpillar, the eggs sometimes available mail-order in the UK and USA.

Is there anything you would particularly like Morus Londinium to do or achieve?

Continue logging the whereabouts of mulberry trees (both black and white). Map those that were inside the Roman walls (Romans introduced mulberries) and those that were within the later London walls. Map those outside the London walls. These maps might indicate old gardens.  And perhaps add a different colour for those with a religious connection, such as those in church gardens etc.

[1] J. Feltwell, The Story of Silk, Alan Sutton Publishing, Stroud 1990.

Article by John Feltwell and Peter Coles.
Pictures from Wikimedia and John Feltwell.