Abstract: Some plants of the cortege floristic of the cork oak, such as the case of the lavender in this study may be favorable to the juvenile growth of cork oak. Thus, plants nurses facilitate the ecological restoration of forest areas degraded greatly, mycotrophic, which can ensure the restoration of mycorrhizal power of soil, thus favoring the good development of the plant cover. The objective of this present study was to evaluate the synergistic effect produced by the presence of plant nurse (Lavandula stoechas L.) and the inoculation of mycorrhizae (Ectovit and Symbivit) on the growth of cork oak. For this purpose, a test of controlled mycorrhization in the nursery has been realized on a twenty plants of this plant grown in polyethylene bag in the presence or absence of lavender (Lavandula stoechas L.) based on plant of cork oak and 10 plants of lavender per bag. The substrate is a soil came from the cork oak forest of Brabtia (Northeastern Algeria), whose condition is well degraded. Non-inoculated controls with and without lavender were provided. After 12 months of growth, the statistical study according to the LSD test showed that cork oak inoculated and not in the presence of lavender had the highest rates of mycorrhization, respectively, 49.59% and 43.66% the same for the total biomass such as 25.02 g and 19.55 g compared to the treatments in absence of lavender as 15.63 g and 12.59 g.