Thornless Blackberry Jumbo - Rubus fruticosus

The Jumbo Mulberry is a thornless variety of garden blackberry, ideal for enjoying its large, shiny black fruits without getting pricked! The harvest takes place once the fruits are ripe, from August to October. These fruits are perfect for eating fresh or making fruit juice. Their slightly acidic flavor is delicious. The Jumbo Mulberry is resistant to diseases and can withstand temperatures as low as -18°C (-0.4°F).

The Mulberry belongs to the genus Rubus, which originated in the mountains of the Caucasus in Asia Minor. The genus has diversified over time and has given rise to several subgenera, including the raspberry (Rubus idaeus) and the common blackberry (Rubus fruticosus). The latter genus includes numerous subspecies that differ in size, colour, and acidity of the fruit. In Europe and America, this berry has been consumed for about 2000 years. The European-origin Jumbo Mulberry belongs to the subgenus Rubus fruticosus and is part of cultivated blackberries.

Hardy and easy to cultivate, the Jumbo Mulberry thrives in ordinary soil, with a preference for fertile, well-drained, and fresh soil. It will do well against a sunny or partially shaded wall, showcasing the bare wood of its flexible branches in winter. Garden blackberries are hybrids derived from the thornless Common Bramble, Rubus var. inermis, itself obtained by crossing the bramble and the raspberry. Extensive improvement and selection work has resulted in numerous thornless varieties, most of which are of American origin and highly productive.

The Jumbo Mulberry is a climbing perennial plant with a semi-shrub and bushy habit. The branches can reach a length of 2 to 3 meters (7 to 10 feet), and the stump can occupy 0.5 meters (2 feet) of ground. These branches will need to be trained: fence, wire mesh, trellis, pergola, arches, there are many options.
The foliage is deciduous, bright green, composed of compound, serrated leaves with visible veins, very similar to raspberry leaves. The stems are thornless. They only live to bear fruit (2 years) and are gradually replaced by suckers sprouting from the stump.
The abundant and nectar-rich flowering displays numerous small white-pink flowers, 1.5 to 2 cm (1in) in diameter, grouped in clusters. It occurs from May to June, starting from the first year of planting.

The fruits that form are composed of agglutinated drupes attached to the receptacle. They are large in size, much bigger than those of wild blackberries, turning red and then black when ripe, from August to November. They should be picked when fully black, as they become sweet, slightly acidic, juicy, and flavorful. The fruits can be eaten fresh right after picking, used for jellies, jams, tarts, or even sorbets, syrups, and juices. They can be perfectly preserved in the freezer.