When can citrus be budded?

Q: When can citrus be budded?

A: When sap is flowing and there has been a recent growth flush so that the bark is still slipping. Buds are taken, preferably from an upper section of the tree, not a watershoot with spikes. Leaves are removed leaving part of the leaf stalk. The budwood can be grafted immediately or kept in the fridge for up to six weeks.

Avocado grafting techniques?
Why do oranges look quite green in the tropics?