root
at the grass roots: seegrass.
put down roots begin to lead a settled life in a particular place.
root and branch used to express the thorough or radical nature of a process or operation.
2005Lucy KellawayWho Moved My Blackberry? Suggest you do not attempt to come home unless you are prepared to undergo a root and branch personal rebranding.
strike at the root (or roots) of have a potentially destructive effect on.
take root become fixed or established.