Summary. The results of the cross R. impeditum × R. ‘Elizabeth’ (R. forrestii var. repens × R. griersonianum), a lepidote and an elepidote Rhododendron can be influenced by temperature. In the phytotron this cross was clearly more successful at temperatures below 20°C than at higher temperatures. Practical experience has shown that the reciprocal cross does not yield seed. The long style of R. ‘Elizabeth’ has to be regarded as a barrier which prevents the tubes of the pollen of R. impeditum from reaching the ovary in time.