Improve grape vines growth?

Hi We live on a hill in Burnaby facing south. I made a special pergola 4m long 2m tall to grow a green and red grape wine. I put a small rose bush on the bottom as do in South Africa, they say if the roses will grow the soil is ok for grapes. After two years one has reached the 2m and grown 1/2 m along the other just 1.75m. They get get sun from morning till mid afternoon and then mixed through a tree on the street .