Dirksen Thornless Mulberry Variety Fact Sheet
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Fruit flesh color: Juicy, pulpy and tender
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Skin color: Shiny black when ripe
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Size and shape: Large (2.5 to 4.0 cm long), oval, weight 6 to 8 grams per fruit
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Tree size: Semi-climbing, reaching 2.5 to 3 meters in height and 1 to 2.5 meters in width
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Fruit maturity: End of July to September
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Fruit Taste: Sweet, slightly tangy, rich and aromatic. Juicy and tender texture, melting and not grainy.
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Earliness of the variety: Mid-season to late
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Fruiting period Late July to early September (main), sometimes until October
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Disease resistance and storage: Good disease resistance. Medium to soft firmness limits long storage outside of cold storage, but fruit holds well on the plant.
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Variety yield: High, generally 4 to 6 kg per adult plant per year, reaching 15 to 20 kg per plant at maturity in conventional cultivation.
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Is this variety self-fertile? Yes
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Commercial use: Fresh consumption, processing into jams, jellies, coulis, syrups, sorbets, ice creams, pastry desserts. Also suitable for freezing.
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Comments: Thornless variety, which greatly facilitates manual harvesting and reduces the risk of injury and damage to the fruit. Native to Illinois, USA (introduced in 1967). Propagated mainly by stem or root cuttings (free-standing), which ensures varietal fidelity and good vigor. The juice content is high, estimated at between 85% and 88% of the fresh weight, making it particularly suitable for the production of juices and other processed products. Very productive from the second year of planting, with an optimal yield from the 3rd or 4th year. Good hardiness (down to -15°C to -23°C depending on the source) and good disease tolerance. Prefers well-drained soil and a sunny to partial shade exposure.
Quick read / the essentials on Mulberry Dirksen Thornless
The 'Dirksen Thornless' mulberry tree is a benchmark among thornless varieties, both for its high productivity and ease of cultivation. Developed in the United States in 1967, this variety is now perfectly suited to professional cultivation in France, particularly for market gardens seeking performance and practicality. Thanks to its large, shiny black fruits, juicy, sweet, and slightly grainy, it is equally attractive for fresh consumption and for processing (jams, coulis, pastries, etc.).
At Bairiverse , a specialist wholesale supplier of Mulberry plants , we support professionals in their choice of robust, self-fertile, vigorous and durable plants. The 'Dirksen Thornless' variety is distinguished by its easy harvest (up to 40% faster than thorny varieties), remarkable hardiness (down to -23°C), and very good resistance to disease, which makes it an asset for producers in both conventional and organic agriculture.
Are you looking to buy Dirksen Thornless Mulberry plants to develop your plot? Trust our expertise. As a specialist wholesale supplier of Mulberry plants , Bairiverse offers you complete support, from advice to delivery, for a successful planting. Don't wait any longer to buy Dirksen Thornless Mulberry plants from a trusted professional: we provide you with a rigorous selection of certified, high-performance plants, ready to produce up to 20 kg per plant for nearly 20 years. Whether you produce for the fresh market, processors or direct sales, buying Dirksen Thornless Mulberry plants from a reliable partner like Bairiverse is a profitable and sustainable decision.
Origin and general description
The 'Dirksen Thornless' mulberry tree is an American horticultural selection , developed in Illinois in 1967. It belongs to the category of thornless mulberries, cultivated for its large fruit , its sweet flavor , its very good productivity , and its ease of cultivation . This variety is self-fertile , vigorous , and suitable for professional production in France.
Fruit characteristics
The fruits of 'Dirksen Thornless' are glossy black when ripe , oval to elongated in shape , reaching 2.5 to 4.0 cm in length and weighing 6 to 8 g in good condition. The flesh, probably dark, is juicy , sweet , slightly acidic and aromatic , with an estimated sugar content of between 9 and 11°Brix . Their juice content exceeds 85% , and the graininess is very low , which favors fresh or processed consumption. Their medium to tender firmness suggests good freezing suitability but limited storage outside of refrigeration.
Recommended uses
Thanks to its taste and physical qualities, this variety is ideal for fresh consumption , but also for processing (jams, jellies, coulis, sorbets, syrups, pastries, juices). It is also suitable for direct sales, markets and large-scale distribution , particularly in refrigerated or frozen trays.
Ease of harvesting
The complete absence of thorns allows for quick , safe and comfortable picking, reducing harvest time by up to 40% compared to thorny varieties. The semi-climbing trellised structure makes the fruits very accessible. This criterion makes it a variety of choice for farms with limited labor or for direct harvesting for sale on the farm.
Performance and longevity
An adult 'Dirksen Thornless' plant can produce 15 to 20 kg of fruit per year in conventional cultivation , and 10 to 15 kg in organic farming , from the 3rd or 4th year . In optimal conditions, 4 to 6 kg can be achieved per season . Productive longevity extends from 12 to 18 years , or even up to 20 years in favorable conditions.
Vigor, habit and cultural requirements
The plant has high vigor (rating 4/4) with a semi-bushy shape to be trained . The stems, flexible and without thorns , can measure up to 5 meters long . The root system is fibrous and superficial , active mainly between 20 and 40 cm deep .
Strong staking with 2 to 3 horizontal wires up to 2 m in height is recommended. Planting can be done from September to November or from February to April . Annual winter pruning is essential to maintain vigor and fruiting.
Flowering and fruiting
Flowering takes place between May and July , with white to pinkish-white flowers, nectariferous and melliferous. The variety is non-remontant , fruiting only once between the end of July and September , depending on climatic conditions.
Resistance to diseases, parasites and stress
'Dirksen Thornless' is renowned for its excellent resistance to fungal diseases : powdery mildew, anthracnose, rust, grey mold , with less than 5% losses under conventional management. It is also relatively unaffected by pests , particularly mites, Colorado beetles and aphids . Compared to 'Thornfree' or 'Black Satin', it exhibits more stable behaviour in humid climates .
Hardiness and climate adaptation
Its hardiness is excellent, with a minimum tolerance of -15°C , and returns reporting up to -23°C . It is therefore suitable for all French regions , even in harsh winters.
Resistance to soil constraints
The variety moderately tolerates root asphyxiation and is sensitive to poorly drained soils . Its resistance to limestone is average ; iron chlorosis may appear above 5% active limestone . Drought resistance is average to low , requiring water input, especially during fruiting .
Fertility and pollination
'Dirksen Thornless' is self-fertile , no pollinator is required. However, co-planting with other varieties such as 'Thornfree', 'Loch Ness' or 'Navaho' can improve yield through cross-pollination , but is not essential.
Reproduction and rootstock
Propagation is traditionally done by root or stem cuttings . Grafting is not recommended , except in cases of restrictive soil, in which case grafting onto wild Rubus fruticosus can be considered, although not standard.
Comparison with other varieties
Compared to references like 'Loch Ness', 'Navaho' or 'Black Satin', 'Dirksen Thornless' offers higher vigor , superior hardiness , remarkable ease of harvesting and very good resistance to organic cultivation . It stands out in particular for its large fruit size , its juicy texture , and its natural resistance to pathogens .
To summarize: Dirksen Thornless Mulberry
The 'Dirksen Thornless' mulberry tree is a strategic choice for professionals wishing to combine profitability, ease of harvesting and robustness . Its high vigor, its semi-climbing habit that is easy to train and its absence of thorns significantly reduce cultivation constraints. Thanks to an average production of 15 to 20 kg per plant in conventional cultivation, this variety represents a relevant response to the expectations of the French markets, whether for fresh or processed fruit.
With Bairiverse, a specialist wholesale supplier of Mulberry plants , you benefit from professional support, rigorous sourcing and advice adapted to your growing conditions. The 'Dirksen Thornless' variety, with its sweet fruits and long productive lifespan, is ideal for planting in sustainable or organic farming. Thanks to its honey-producing flowering and excellent resistance to diseases such as powdery mildew, rust or grey mold, it meets the technical requirements of demanding producers.
If you are considering purchasing Dirksen Thornless Mulberry plants , contact Bairiverse. As a specialist wholesale supplier of Mulberry plants , we help you select the best-performing plants based on your soil, climate, and yield goals. Buying Dirksen Thornless Mulberry plants means choosing a reliable variety that is suitable for partial harvest mechanization and fits perfectly into both short and large supply chains. To successfully produce quality blackberries, buying Dirksen Thornless Mulberry plants from Bairiverse is a guarantee of reliability, performance, and sustainability.
