Here’s a riddle. What grows to 10 metres tall, has fruit like a raspberry, but is related to a fig? The fruits taste divine, but it was popularised in England not for eating, but as a food source for caterpillars.
Those who know their history or botany will have gathered that the answer to the riddle is the mulberry tree (Morus nigra). King James I planted thousands near the grounds of Westminster Palace in an attempt to wrest control of the silk industry from the French. Thousands of seeds and young plants were also distributed to estates, colleges and churches across the land to be planted by royal edict. Unfortunately, the silk moth caterpillars prefer the white mulberry (M. alba) and he had planted the black. But the weaver’s loss was the foragers and the cook’s gain and many of these original trees can still be tracked down growing in public spaces.
Westminster is still fertile grounds for finding these trees. A walk around St James’s park might furnish you with the fruits from the original trees brought over by King James and there is a National Plant Collection of mulberries with over 30 different species and cultivars held in the grounds of the Buckingham Palace.
Deep purple fruits
The trees stumble drunkenly through our parks and the remnants of grand estates, characterised by their gnarled bark, twisted shape and habit of leaning, falling over and re-rooting. Late to come into leaf and without showy flowers, most wouldn’t get a second glance until August, when the dry, green fruits flush red, then burst into deep purple.
The fig connection is easiest to see in the milky white sap, but the taste is close to a blackberry, though both sharper and sweeter and far, far juicier.
This tree names and stains the guilty who steal its fruit – no matter how careful you are, you will end up with hair, face and clothes splattered with wine red juice. This is maybe why you will never see the fruit for sale. The fruit is either under ripe and won’t part from the tree or just right and bursts in your hand. Most of the fruit is also out of reach for all but the very nimble or owners of cherry pickers. This is probably why there are just a handful of mulberry orchards in the UK, with the fruits harvested for jam making.
In 2017 a new chapter was started in the history of mulberries in the UK, with the introduction of a dwarf mulberry ‘Charlotte Russe’. This grows to no more than 150cm, so suitable for pots and small gardens. It will fruit in just a few years too rather than waiting for up to decade for the large tree to start fruiting. I have heard mixed opinions on the quality of the fruit – pleasant, but not a patch on the full size specimens. However, much of the flavour in fruit is down to growing conditions and the weather so I would say it is worth giving it a second chance.
So for those who don’t like to take a gamble on flavour, or those who like to go out on a foraging adventure, I can’t recommend highly enough the website of the Morus Londinium project. This has been hunting down and mapping mulberries in London, but also expanding to mulberries further afield. Many are in public parks or the grounds of large estates, often as a remnant from older plantings. This is a great resource if you want to hunt some down, but bear in mind that any attempts at theft will result in being caught red handed!