This grower is sure of this plant identification.
in an 80 litre pot, so its really heavy, but at this time of year bare root is fine
Common mulberry, Black mulberry, Mulberry
Morus nigra (Common mulberry). This small to medium sized tree develops a wonderful gnarly trunk and will produce dark red berries in late summer/early autumn that can be eaten fresh or used in pies or for jams. Beware the fruit on clothes as it stains easily.
They will grow in a wide range of conditions, but do best in fertile, well-drained soil with a sunny, sheltered position. You can propagate from cuttings.
Specimen and fruit