Camellia Sinensis (the tea tree) is actually a TREE but human beings over centuries have turned it into a SHRUB, so it remains at a convenient height for us to pick the leaves. If the tea tree is not pruned (maintained) during off season (January/February) the tree like any other tree can grow upto 40 feet tall.
The image above is of a tea tree (approximately 10 feet tall - from our nursery) which has been recently pruned - the leaves are still on the ground since it acts as organic fertilizer. We don't use the Mother Tea Tree for tea leaves, but rather for seeds with which new Tea Saplings will be planted. It’s essentially the mother plant from which many babies will be born.