Rubus fruticosus 'Dirksen'

The 'Dirksen Thornless' Garden Blackberry is a robust, hardy fruit undershrub. To simplify cultivation, its semi-rigid stems, 2 to 3 metres (7 to 10 feet) long, can be trained like a climbing plant. It produces large black fruits on thornless branches, which significantly facilitates harvesting. From August to October, an abundance of juicy blackberries with a balanced sweet-sour flavour can be harvested. This sweet taste, punctuated by a slight acidity, provides a lot of pleasure when eaten. Fruity and aromatic, this fruit enhances sauces, jellies, jams, pies, and fruit salads with its colours and fragrance—recommended planting in autumn.

The Rubus belongs to the rose family and is native to the mountains of the Caucasus in Asia Minor. This 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 fruit size, colour, and acidity. This berry has been consumed in Europe and America for about 2000 years. Rubus fruticosus is commonly known as the bramble or wild blackberry. It is a climbing liana that can reach a width of 5 metres (16 feet) or more, with branches usually covered in thorns. It is found in many temperate regions worldwide, where it is often considered an invasive plant.

Rubus fruticosus 'Dirksen Thornless' is a garden blackberry of American origin, selected for its large fruits, thornless branches, and high yield. It is a climbing perennial plant with a semi-shrubby and bushy habit. The branches reach a length of 1.50 to 2.50 metres (5 to 8 feet), and the stump can occupy 0.5 to 0.8 metres (2 to 3 feet) of ground space. The foliage is deciduous and falls in autumn. It is bright green and composed of small, serrated leaves with visible veins similar to raspberry leaves. The branches only live to bear fruit (2 years) and are gradually replaced by shoots emerging from the stump. Fruit production generally occurs on 2-year-old branches, so renewing them yearly through winter pruning is essential. From May to June, the abundant and melliferous flowering consists of numerous small white flowers, single and cup-shaped, measuring 1.5 to 2 cm (1in) in diameter, grouped in clusters. The growing fruits are called drupes, clustered together on the receptacle and remain attached. They are larger than wild blackberries and change colour from red to black and shiny when they are fully ripe. They are best picked when they are entirely black when they are sweet, tangy, juicy, and flavorful.

'Dirksen Thornless' Blackberry has abundant fruiting from mid-August to October, allowing for staggered harvests for various culinary uses. It is a delicate fruit that must be picked carefully. Light rinsing with water is possible. Blackberries keep better in the refrigerator and can be frozen. The large size of the fruit on thornless branches greatly facilitates harvesting. They are enjoyable to eat fresh right after picking. They can also be used for various culinary purposes, such as jellies, jams, sorbets, sauces, syrups, juices, tiramisu, crumbles, and puddings... not to mention the famous blackberry pies. Low in calories but rich in minerals (manganese, iron, potassium), vitamins C and K, fibre, and antioxidants, blackberries contribute to a balanced diet.

Hardy down to -20°C (-4°F), easy to cultivate, the 'Dirksen Thornless' Garden Blackberry thrives in ordinary, preferably fertile, well-drained, and moist soil. A sunny or slightly shaded exposure is preferable. It is advisable to train the branches as they grow on a support such as a fence, trellis, pergola, or arches to facilitate harvesting. In winter, the branches that bore fruit that year should be pruned back to 15 cm (6in) above the ground. Mulching helps reduce evaporation and preserves soil fauna.