Morus nigra

Tree of the Week - Entry 3 - August 2026

You'll know it's mulberry season before you see the tree. You'll see the stains on the patio first. Right now, late July into August, a mature black mulberry is doing what it does every year at this time: ripening its fruit and dropping it, all at once, dark red going to near-black, sharp and sweet together, closer in character to a large blackberry than anything else you're likely to grow in a Surrey garden. There's no holding it back and no tidying it up. The tree fruits on its own terms, and that, in the end, is most of what there is to say about it.

It's a medium, spreading deciduous tree, gnarled and characterful with age, capable of reaching around 9 metres tall and as wide given the room. It's self-fertile and genuinely long-lived. The reason you almost never see the fruit in a shop is simple: it doesn't ripen and hold, it ripens and drops, and once dropped it's too fragile and too fleeting to transport anywhere. The RHS describes the flavour as "deliciously sweet, aromatic and tangy", and that's about right. Better in flavour than either red or white mulberry, sharper and more complex. If you have one, late July is the month that decides whether you love it or curse it. Both responses are reasonable.

Beneath the soil

Look low down on an old specimen. Half those sprawling branches have been quietly doing something for years. Old black mulberries develop a distinctive habit as they age: the lower branches lean, sag, and eventually touch the ground, and where they do, they can take root themselves - effectively cloning the tree at its own feet. On a mature tree you can see this happening, a low branch half-buried, rooted, still attached to the parent. It's part of why old mulberries look sprawling and improvised rather than neatly shaped. They've been propagating themselves for decades.

The craft angle here is a genuine curiosity. Most fruit trees in this column are grafted onto a related rootstock chosen for vigour or size control. Black mulberry does something stranger. It's notoriously reluctant to root from its own cuttings, so where a grafted tree is wanted, nurseries commonly take scion wood from Morus nigra and graft it onto the roots of Morus alba - the white mulberry, a different species entirely - chosen simply because it roots and grows far more willingly. The tree you buy may genuinely be two species working as one: black fruit above, white mulberry roots below.

Establishment favours moist, humus-rich, fertile soil, with shelter from cold, drying winds while the tree is young. Formative pruning matters, but timing is everything: prune in late autumn or early winter, well after leaf fall. Mulberries bleed sap heavily if cut while active, and a wound made in spring can weep for weeks.

Practical use

The fruit is the whole point. Eaten straight from the tree - ideally over a towel rather than good clothing - or used quickly in jams, syrups, and puddings, since it doesn't keep once picked. Beyond the kitchen, it's a fine specimen tree for a large lawn, offering shade, decent autumn colour, and enough character in its bark and branch structure to be worth looking at even without fruit.

A seedling-grown tree can take around eight years to fruit properly, so a named, grafted variety is usually the better choice if fruit sooner rather than later is the aim. Named varieties often come into fruit more quickly than seedlings, and some of the more compact modern forms are bred to stay small - useful where space is genuinely tight. The variety 'Charlotte Russe', for instance, will reach only 1.5 metres if kept in a container and will fruit in its first year. Training as a wall espalier against a warm, sheltered wall is another way to bring a mulberry into a smaller, more structured garden without sacrificing the fruit.

Care and mistakes

Worth doing:

• Choose planting position carefully before the tree goes in - this decision is much harder to undo later.
• Plant in full sun with shelter from cold winds.
• Choose a named, grafted variety rather than a seedling if you want fruit within a reasonable number of years.
• Prune in late autumn or early winter, after leaf fall, to avoid sap bleed.
• If space is limited, consider a compact variety or wall-trained espalier from the outset.

Worth avoiding:

• Don't plant directly over a patio, path, seating area, or anywhere pale and hard to clean - dropped fruit stains everything it touches and there's no way round that once the tree is fruiting well.
• Don't prune in spring or summer when the tree is in active growth.
• Don't plant a full-size seedling tree in a small garden and expect to keep it in check - choose the right form for the space at the start.
• Don't crowd the root zone with dense underplanting - the canopy casts a fair amount of shade and the roots are best left relatively undisturbed.

Context and companions

Mulberries have a long association with grand old gardens and historic houses rather than tidy modern borders, and they suit that kind of setting best: a lawn, an old wall for shelter, room to sprawl. A spot over rough grass or bare soil, where fallen fruit can simply be left, works far better than anywhere manicured. The canopy casts reasonable shade and the root zone is best left undisturbed rather than crammed with underplanting, so this isn't a tree that invites a busy mixed border beneath it.

For a Surrey garden with a warm, sheltered wall and limited space, the espalier approach is worth considering seriously - it trades the sprawling old-tree habit for a disciplined, productive shape that can sit comfortably in a smaller plot.

Questions people actually ask

The question about slow fruiting comes up every time. If a tree is seedling-grown rather than a named grafted variety, eight years or so is genuinely normal. It's not sulking; patience is simply part of the deal with this one, and named varieties are the practical answer if waiting eight years isn't appealing.

People also ask whether the staining can be prevented. Not really - other than choosing the planting position carefully in the first place, or accepting a season of hosing down paving. The fruit drops when it's ready and it stains everything it touches. That's the honest answer.

There's a regular question about silkworms. The silkworm's tree is the white mulberry, Morus alba - a different species. Black mulberry is grown for flavour, not for silk production, though the two are sometimes confused, and the cross-species rootstock relationship described above means the two are more entangled in cultivation than most people realise.

And on keeping it small: yes, it's possible, but the route there is choosing a genuinely compact variety or a wall-trained form from the outset, not trying to restrain a full-size seedling tree once it's established.

If you'd like to see Morus nigra in person, or talk through which form suits your garden and space, come and find us at Cedar Nursery in Cobham, Surrey. Our team is happy to help you choose the right tree and get it off to the best possible start.

Featured image: Photo by DaMLa on Pexels

Come and stand under it. Cedar Nursery, Cobham, Surrey.