Raspberry-blackberry hybrid (Rubus hybrid) BOYSENBERRY

Boysenberry (Rubus hybrid)

The 'Boysenberry' is an exceptionally complex interspecific cross combining the genetics of the European raspberry (Rubus idaeus), European blackberry (Rubus fruticosus), American trailing blackberry (Rubus aboriginum), and the older 'Loganberry'. The result is a fruit with an absolutely delicate, unrepeatable taste. Due to its extreme tenderness and short shelf life, it has almost completely disappeared from supermarket shelves (in the US), making it an exclusive treasure for home gardeners today.

Boysenberry (Rubus hybrid)

The result is a fruit with an absolutely delicate, unrepeatable taste. Due to its extreme tenderness and short shelf life, it has almost completely disappeared from supermarket shelves (in the US), making it an exclusive treasure for home gardeners today.

Main advantages of the variety:

• Absolute top-tier, complex sweet-tart taste (considered one of the tastiest berries ever).
• Large and exceptionally juicy fruits.
• Ideal for processing – jams, syrups, pies, and ice creams made from it have an unsurpassed color and aroma.
• High yield when properly trained on a trellis.

Origin and Breeding

• Rescue at the last minute: The exact origin is not entirely clear, but the variety is named after Californian grower Rudolph Boysen. He experimented with it, but later sold the farm and abandoned the plants. In the late 1920s, George M. Darrow of the US Department of Agriculture heard about the "big purple berry." Together with berry expert Walter Knott, they found the last few stunted shoots surviving in weeds on Boysen's old farm.
• Birth of a legend: Knott transplanted the plants to his farm, saved them, and began selling the fruits in 1932. Customers returned in such numbers that the Knott family's small stand eventually grew into the world-famous theme park and food brand Knott's Berry Farm.
• Commercial rise and fall: In the 1950s, 'Boysenberry' cultivation in California peaked, surpassing even regular raspberries and blackberries. However, a decline came in the 1960s. The fruits were too soft for transport, prone to mold, and had a short season. Today, New Zealand is the world's largest producer and exporter (especially of processed puree and jams).

Detailed variety description: Plant

• Vigor: The plant has a typically trailing (prostrate) habit. It does not form upright canes like raspberries, but long, flexible shoots that trail along the ground. The original variety is thorny, but thornless mutations were bred in New Zealand in the 1980s.
• Lifespan: It is a long-lived perennial that will last 15 to 20 years in the location with proper care.

Fruits and Flavor Profile

• Appearance and size: The fruit is a large aggregate of drupelets (weighing an average of around 8 grams). Upon ripening, it changes color to a deep, dark maroon-purple. Contains medium-sized seeds.
• Texture: The skin is extremely thin and the fruits are exceptionally soft. At full ripeness, dark staining juice escapes at the slightest pressure.
• Taste: This is the main reason to grow this variety. It offers a perfect balance – sweet-tart, with a rich, complex profile combining the aroma of wild raspberries and wild blackberries.

Cultivation properties and agrotechnics

• Environmental requirements:
  • Location: Requires direct, full sun.
  • Soil: Fertile, loamy, and above all well-drained soil is ideal. Optimal pH is slightly acidic, ranging from 5.6 to 6.5.
  • Moisture and nutrition: Responds well to nitrogen fertilization at the beginning of the season. Mulching (with bark or straw) is recommended to suppress weeds and retain soil moisture.
• Trellising and tying (Crucial for success):
  • Since the shoots are trailing, cultivation without support is impossible (fruits would rot on the ground). Requires a solid trellis. Plants are planted 60 – 75 cm apart, with row spacings of 2.4 to 3 meters. Shoots are gradually tied to wires.
• Pruning and fruiting:
  • Like most blackberries, 'Boysenberry' fruits on one-year-old wood (from the previous year). Shoots that have fruited in a given year die back in autumn and must be cut off close to the ground. Young shoots (grown in the current year) are tied to the trellis and will bear fruit in the following season.
• Pollination:
  • Flowers are self-fertile, but the presence of bees and bumblebees is important for perfect pollination and nice fruit shape.

Drawbacks of the variety:

• Soft fruits – cannot be stored, begin to degrade and ferment within a few days (often hours) after harvest. Must be eaten or processed almost immediately.
• Trailing habit requires tying to support and regular pruning.
• In very wet weather, soft fruits are more susceptible to fungal diseases (especially gray mold - Botrytis).
• Original form has thorns (it is advisable to look for modern thornless clones when purchasing).