I would say it would be: Radnes'
In this sentence: If Radnes' dog growls at one more person, they will have to put him down.
The possessive form of the proper noun Henry is Henry's.Example: Henry's party is this Saturday.
The possessive form of the proper noun Lucky is Lucky's.Example: Lucky's collar has his name on it.
The possessive form for the proper noun Kiersha is Kiersha's.Example: We're going to Kiersha's house.
The possessive form for the proper noun Richter is Richter's.Example: Mr. Richter's class is in room two hundred.
Turner is a proper noun (a name). Turner's is the possessive form.
The possessive form of the proper noun Mattice is Mattice's.Example: Dr. Mattice's office is in building two.
The possessive form of the proper noun Izzy is Izzy's.Example: The name of Izzy's dog is Spot.
The possessive form of the proper noun Cox is Cox's.Example: This is Mr. Cox's book.
The plural form of the proper noun Charles is Charleses.The plural possessive form is Charleses'.Example: The two Charleses' last names are White and Green.
The possessive form of the proper noun Heintz is Heintz's.Example: Mr. Heintz's classroom is down that corridor.
The word Pegasus is a proper noun, the name of a mythical creature, and should be capitalized. The plural possessive form is Pegasuses'.
The plural form of the proper noun Thomas is Thomases.The plural possessive form is Thomases'.Example: The Thomases' children are twin boys named Jack and Jim.