I didn't know they had to be planted on hills. Will they still produce pumpkins...because I have none yet and vines are real long.
Certified GKH Gardening Expert
Planting in hills certainly will help with water drainage, though this is ideal, many other conditions go into a healthy producing vine.
Adequate watering, full sunshine and pollination are also needed for your vines to produce.
Here are some links to help refresh you on the care requirements.