The 99 Richter rootstock, or 99 R, is a hybrid widely used in vineyards across the globe, particularly in Bordeaux. Developed following the phylloxera crisis, it is valued for its moderate vigour and good tolerance to certain soil types. Its adaptation to varied conditions makes it a relevant choice for winegrowers seeking to optimise the balance of their vineyard.

Origin and creation of the 99 Richter rootstock

The 99 Richter rootstock is the result of a cross between Vitis Berlandieri and Vitis Rupestris. This hybridisation was carried out by Richter, within the context of searching for robust solutions to combat phylloxera, which was devastating European vineyards in the late 19th century. The objective was to combine the lime tolerance of Vitis Berlandieri with the adaptation to dry soils and good graft affinity of Vitis Rupestris.

Rootstock profile

Characteristic	Description
Parentage / cross	Vitis Berlandieri x Vitis Rupestris
Species of origin	Vitis Berlandieri / Vitis Rupestris
Breeder and date	Richter, late 19th century
Resistance to phylloxera	Good
Conferred vigour	Moderate
Tolerance to active lime	20% / IPC 30
Drought tolerance	Good
Tolerance to humidity / waterlogging	Moderate (sensitive to hydromorphic soils)
Effect on scion ripening	Neutral to slightly delayed
Status / registration	French official catalogue

Adaptation to soils

99 R shows good adaptation to calcareous soils, with a tolerance to active lime of up to 20% and an IPC (Chlorosis Power Index) of 30. This characteristic is inherited from Vitis Berlandieri. It is also well-adapted to dry, stony soils, but proves more sensitive to wet, waterlogged soils, where poor drainage can compromise its development. Its ability to thrive in poor or shallow soils makes it a versatile rootstock for many winegrowing terroirs.

Conferred scion behaviour

This rootstock confers moderate vigour to the scion, promoting a balanced canopy and consistent production. It tends to induce neutral to slightly delayed ripening in grafted grape varieties, which can be an asset in warmer regions to preserve aromatic freshness. 99 R provides a steady supply of water and nutrients, contributing to consistent yields and berry quality.

Graft affinity and vineyard management

99 R displays good graft affinity with most Vitis vinifera varieties, including those historically cultivated in Bordeaux such as Merlot and Cabernet-Sauvignon. It is well suited to various planting densities and pruning systems, offering flexibility in vineyard management. For soils at risk of root asphyxiation, ensuring proper drainage is recommended.

Sensitivities and limitations

Despite its qualities, 99 R is not without its vulnerabilities. While it tolerates limestone, an excess can still trigger iron chlorosis. It is also moderately sensitive to moisture and can suffer in soils that are too compact or poorly drained. Its use must be tailored to the specific characteristics of the terroir to avoid imbalances, particularly regarding vigour, which—if poorly managed—can sometimes induce coulure (shatter) in certain varieties or under specific conditions.

Value in the face of climate change

Faced with the challenges posed by climate change, 99 R offers notable advantages. Its good drought tolerance makes it an appealing choice for regions prone to arid summer periods. Its neutral to slightly delaying effect on ripening can help avoid excessively early harvests and maintain a fine sugar-acid balance in the grapes, thereby contributing to the adaptation of Bordeaux vineyards to evolving climatic conditions. The 110 R rootstock (110 Richter) is another example of a rootstock with good drought tolerance. The SO 4 rootstock (Selection Oppenheim 4) also offers valuable benefits. We can likewise mention the 1447 P rootstock (1447 Paulsen). Finally, the 5 BB rootstock (Kober 5 BB) is another option for its adaptive capacity.

Château Cazebonne is committed to exploring and preserving the viticultural diversity of Bordeaux, notably through the selection of adapted rootstocks. This work is part of a broader approach aimed at restoring pride to our local ampelographic heritage. To learn more about our commitment, we invite you to download our book "Bordeaux, a history of grape varieties". If you would like to deepen your wine knowledge, feel free to test your skills with our wine quizzes. And to discover the fruits of our labour, browse our online shop and taste our wines.