Grass trimming along a bamboo border

[Mymadlife]

I have a bamboo border edging along my grass. When I mow the lawn there are always long hits of grass growing with the border. How do i trim this to give a neat edge. I used to have an edging tool but it would hot the bamboo. Please advise me otherwise I'll be forever using scissors which aches my hands.

These?

Thank you, I will buy this tomorrow and at least I don't have to plug it in.