Is it true that most trees , shrubs, plants, etc put on their root growth the most in the Autumn and winter?

good time for root growth?... yes.. fall and winter.... that is why it is suggested that folks plant trees and shrubs in fall..... first because the plant and the people don't have to fight the heat and dry conditions of summer on new plants...... second because roots can continue to grow long after we think it is too cold, since the ground is still unfrozen, deeper down where the roots are ....... then, too, the plant doesn't have to expend it's energy on making new leaves, growing top growth or putting out flowers or seeds/fruit... it can put all the energy it has stored all summer into pushing out new roots and do it slowly without a rush for food or water......and late season rains keep the ground moist and soft so that those roots CAN move easily thru it....