"hilly field" is correct and usable in written English.
You can use this phrase to describe a field with hills or a field that has been hilly in shape. For example, "The hilly field was scattered with daisies."
He has been rooting through the rafters for next year's planting stock, some 7,000 bulbs he will bury in a hilly field beside some poplar trees in October.
On both sides of the road, bulldozers had already pushed back the jungle for fifty yards, forming six miles of rough, hilly field that contained torn-up tree trunks, broken branches, and upturned stumps with their roots sticking out in every direction.
There is a sweeping of late winter snow on the surrounding hilly fields.
After dark, their fires crept across hilly fields of stubble, filling the air with smoky haze.
They kept chickens, sheep, cows, and two workhorses, who pulled the plow and old wagon that carried the harvest from the hilly fields to the barn.
Will the new owners of the surrounding fields keep the 16 acres of native grasses — big bluestem and Indian grass, coneflowers and goldenrod — that buffer the stream, absorbing storm water and pesticides from the hilly fields that roll down to the water's edge?
The saddest thing in this world is watching my thin friend march up and down the hilly fields in front of my house because she ate half a chocolate eclair and is now disgusted with herself so much and to such an extent that she has to march, march, march it off.
The development of perennial cultivars (CVs) of upland rice would give farmers a new tool to reduce soil erosion from hilly fields, thereby mitigating a problem of regional concern in Southeast Asia.
On hilly fields, the boom is not positioned parallel to the ground, resulting in an uneven spray distribution pattern and causing harm to the boom when hitting the soil.
I first went to my local bowls club, The Francis Drake on Hilly Fields in Brockley, last summer.
Joey's earliest memories were mostly "a confusion of hilly fields and dark, damp stables".
