Base rootstock is a plantation of “rooted grafted vine plants” — these are rooted cuttings of hybrid wild grapevine species, onto which the noble grapevine (Vitis vinifera) is not grafted. Such plantations are used exclusively for the production of rootstock cuttings, onto which the noble grapevine is grafted. Trsnica Vrhpolje maintains approximately 15 hectares of mother blocks with the following rootstock varieties: SO4, Kober 5BB, Richter 110, and Paulsen 1103.

• The SO4 rootstock is currently the most widely used grapevine rootstock. It is a hybrid of the species Vitis berlandieri and Vitis riparia. This rootstock is well suited for more vigorous soils. It is compatible with all grapevine varieties, but is especially suitable for varieties with strong vegetative growth, as it moderates vigor and thus supports higher-quality yields.
• Kober 5 BB is also a hybrid of Vitis berlandieri and Vitis riparia. It is suitable for rich soils with a higher calcium content and encourages more vigorous vine growth.
• Richter 110 is a double hybrid of Vitis berlandieri and Vitis rupestris. It is a vigorous rootstock, suitable for flysch-based, well-drained soils with high calcium content. From the same origin as Richter 110 is also...
• Paulsen 1103 is also suitable for dry areas; the only difference is that it tolerates slightly lower levels of calcium in the soil.