How to Fix Frost Damage to a Thuja Green Giant

Treatment

• 1

  Wait until spring, then prune back obviously damaged twigs and branches to a green leaf on undamaged portions of the branches. Do not prune back to a spot without leaves, an area inside the tree known as the "dead zone." Pruning into the dead zone will leave a gaping hole; arborvitaes do not sprout new growth within the dead zone. If the branches are broken within the dead zone, cut them back to the trunk or a lateral branch.

• 2

  Search your "Green Giant" thoroughly for additional signs of frost and winter damage. While the most obvious symptoms are normally a few broken twigs or branches accompanied by brown, reddish-brown or yellow leaves near the outside of the tree, frost damage can also damage branches within the tree, as well.

• 3

  Prune all of the newly discovered damaged branches back to undamaged portions of the branches, always to a green leaf.

Prevention

• 4

  Water the arborvitae until late autumn and throughout winter when the temperatures remain above 40 degrees Fahrenheit for a couple of days or more. "Green Giants" prefer average soil, but will tolerate dry and moist locations. During mild, dry winter spells, water as you would during the summer. Give the arborvitae 10 gallons of water for each diameter inch of tree. Because much of the winter damage is caused by transpiration, or the leaves losing too much water, thoroughly watering throughout autumn and throughout spells of mild winter weather can thoroughly reduce the risk of winter damage.

• 5

  Mulch the area under the drip line of the arborvitae with approximately 4 inches of organic mulch; untreated and undyed wood mulch or pine needles work well. The mulch can help stabilize the soil temperatures and protect against transpiration.

• 6

  Place a burlap sack or other protective covering over the arborvitae before freezing temperatures, wind or snowstorms to prevent damage.