A Guide to Growing Mulberries

A Guide to Growing Mulberries

For many, a large part of the attraction of growing fruit is not only the delicious produce, but the sense of history that comes with it. Plant a Court Pendu Plat apple and you can enjoy biting into the very same fruit as the Romans who introduced it into the U.K. some 2000 years ago. Every Bramley apple is a direct descendant of a single tree grown from a pip by Mary Ann Brailsford in her garden in Nottinghamshire in 1809. The Conference pear, even today a mainstay on the supermarket shelves, was so named as it won first prize at the National British Pear Conference in 1885. There is always the temptation of the latest product of extensive breeding programmes, promising record breaking yields and disease-free growth - but more often than not we are drawn to the past and a connection with previous generations of gardeners and fruit growers.

There is one plant that has probably the richest history of all, intertwined with various empires and dynasties, expanding and contracting across the world - the mulberry tree. So let's take a brief look at how this tree has shaped agriculture and trade over the past 4000 years, before moving on to look at how we can continue the story and grow this most prized of fruit in our own gardens today.

The mulberry genus, Morus, first emerged about 63 million years ago. Broadly speaking, there are three main types - red, white and black. The red mulberry is native to the United States, and whilst it is an excellent tree producing sweet fruit, unfortunately it does not seem to travel well and is hard to find and even harder to grow. The white mulberry Morus alba, is an excellent street tree, hardy, grows well in most soils and climates, and it’s leaves are the main source of food for silkworms. Indeed it is this use in the production of silk which has fuelled its spread across the globe, as silkworm farming has grown from its origins in China some 4000 years ago. However it is the black mulberry, Morus nigra, which is our primary focus as fruit growers. The leaves can be used to feed silkworms, if you fancied having a go at sericulture ( the production of silk), but the fruit are a thing of wonder - dark purple black, like elongated blackberries, with a rich sweet- sharp taste unlike any other. The fruit is exceptionally fragile - it turns to mush within a few hours of picking, so you will only ever get to taste it if you have your own tree (or access to a neighbour’s!). On a side note, only the red mulberry is named after the colour of its fruit - white and black refer to the colour of the emerging buds in late spring. Black mulberry fruit is indeed a dark inky purple black, but the fruit of the white mulberry can be white, pink, red or purple.

Black mulberries are normally sold as pot grown plants, so can be planted at any time of year although early spring is best. The roots are brittle and fragile, so take care when transplanting as they are easily damaged. Choose a sheltered site in full sun - although perfectly hardy, they prefer a warm place to do their best. Mulberries will grow in a wide range of soils, but dislike thin, free-draining soils, so incorporate plenty of organic matter when preparing the planting hole. This improves soil structure and helps with moisture retention. In the first few years, it’s well-advised to mulch trees in spring and water well in any dry periods over summer - although once well established, the trees will happily fend for themselves with little needed in the way of fertiliser.

Mulberries grow into large spreading trees - ultimately 7 metres or so tall, and the same across, although it will take a long time to get to that size - so allow plenty of space. They are either on their own roots or grafted onto white mulberry, so it’s not normally possible to grow a ‘dwarf’ tree, but if you have the space a mulberry makes a fantastic ornamental statement tree - showy foliage and knarled, twisted branches which add dramatic structure to the winter garden. One slight word of warning - the fruit stains anything it touches, so avoid planting near a path (or next to a parking space!)

Mulberries require little, if any, annual pruning. Remove any damaged or unwanted growth in early winter, as mulberries are prone to bleed sap if cut when in active growth. They are naturally unruly in growth, which is part of their charm - the organic shapes of an established tree are a wonder to behold. If you prefer to have a little more order in your garden, it’s best to use a strong cane or hazel rod to tie the new growth to, to encourage a strong straight central trunk. Mulberries will often send out multiple leaders, so select the strongest and straightest one to tie in, and prune off any others.

There is essentially only one species of black mulberry, so there is not a huge list of varieties to choose from, as there are with other fruit. Some catalogues may list different forms, such as Black Beauty or King James, but there is actually very little, if any, difference between them. The black mulberry has more chromosomes in its cells than any other flowering plant - and it is this complexity which has meant that so few variations have occurred. The species, Morus nigra, is the one which you will find and the one to choose.