Several years ago I planted 5 Boston ivy plants along a wire fence hoping that they would grow to cover the fence entirely. So far they have not grown anywhere near half the height of the fence and actually tend to mound and creep along the ground and not up the fence. How can I make them do what I want? I've tried to encourage them by training them to climb the fence but they only go as far as I've coaxed them to go and then climb down again.
You may want to have a soil test performed.
This will tell you what you may be lacking in the soil.
Here is a link to refresh you on the care requirements.