My mothers Zakat year runs from Ramadan 1441 to Ramadan 1442 so she has Zakat due since she has had savings above Nisab for a full year.
However, what happens to any money she received from sale of property/land in Dhul hijjah 1441 (so she has had this money for less than a year) does she add it to the Zakat paybale in Ramadan 1442 or wait until Dhul Hijjah 1442 to pay Zakat.
May Allah bless you.
On her zakat anniversary date, she will include all the zakatable assets that she has, into her zakat calculation. This is irrespective of whether she has some of this wealth for less than a year.
*P.S: Holding zakatable assets for a full year period, is a valid principle among many scholars, but it is also a misunderstood one among the laymen. * If people were to apply this principle correctly, they would probably end up paying zakat multiple times in a year, as opposed to once only.