First time blackberry gum auto outdoor

This week the weather has been much better with plenty of sun. The plants have slowed down growth vertically but the side branches are growing fast now and the buds have also grown bigger in the past week. Due to the cold temperatures at night one plant has turned even more purple with the leaves also turning purple. Some of the lower leaves, the older leaves are turning yellow and dying is this normal? Hopefully harvest comes soon because night temps are expected to keep decreasing in the next few weeks. Winter is coming :(