Grub out
Definition 1 of 2
Pro Tip 1/3Physical Action
Refers to actual digging and removing plants or roots by hands or tools. 
After the harvest, we grubbed out the leftover crops.
Pro Tip 2/3Gardening Context
Often used in gardening or farming settings to clear land. 
My weekend was spent grubbing out weeds from the garden.
Pro Tip 3/3Hard Effort
Implies a task requiring effort or force, not a gentle process. 
It was tough to grub out the bushes; the roots were deep.