Red Dragon Japanese Maple barks splitting from trunk.
Outside United States
Thank you for contacting us. Japanese Maples are particularly prone to cracking bark. Is the cracked portion facing south or west? If so, this is generally due to sunscald or frost cracks.
Frost cracks occur in the winter when temperatures are below freezing but the sun quickly warms the trunk. The freeze-thaw cycle may continue for an extended period of time and eventually loosens the bark. To avoid this in the future, you can lightly wrap burlap around the trunk (without constriction) during the winter. Alternatively, you can simply place a plank of wood against the trunk on the exposed side. Shading the bark will help prevent further cracking.
Do not put anything on the current wounds. The tree should heal itself over time.
Thanks for the quick response.
Right now because the weather is so nice hot and warm, I will leave it the way it is but what should I do when the winter come? The tree is doing good right at the moment except for some dead branches and scorching leaves as normal in the summer because of the heat and sun.
You don't need to do anything right now except keep the tree watered if it does not rain, and keep mulch across the drip zone of the tree. Trees need 1 to 2 inches of water per week, and it is best to do a long, slow trickle of water that gradually soaks in deeply. You can also top-dress with mature compost at any time.
You can prune out dead wood anytime, however, first make sure the branch is truly dead. Scratch the branch with a fingernail to see if there is any green under the bark. But if it is dry and brown all the way through, the wood is indeed dead.
For the winter, the only thing you need to do is protect the bark from direct sunlight. This should help prevent further damage and allow the bark to heal.