Hi, the leaves have curled on 2 branches on my potted Acer palmatum 'Ariadne'. There has been a lot of rain here. The tree gets morning sun and afternoon shade and is in a bark potting mix. The rest of the tree is healthy. What do you think is the cause to the curling leaves and should I cut the branches? Thank you.
Hi, I have had similar problems in the past to maples in pots during continued very wet weather. I believe your problem is too much water and possible compaction causing oxygen depletion. I don't think there is anything you can do for your tree other than some cosmetic pruning now and re potting in the Autumn in a very porous compost mix. (if branches are alive after checking with a finger nail test then you may be fine next Spring without having to prune now). Your Ariadne is much further along than ours. We are still enjoying the Spring colours of this wonderful cultivar here in the uk. Good luck.
Can I add one more comment on your post. All my maples I have in pots are raised off the ground. This further allows for better drainage. I see in your photos that yours is on the ground, this will encourage water logging if the rain water cannot get away fast enough during HEAVY and constant rain. You can purchase feet for pots, but an alternative is three pieces of crocks to raise it a little.
The back branches failed due to lack of sunlight. Further complications due to fungus caused by abundant moisture and lack of airflow. The branches may have been weaker headed into spring (due to lack of light), some call this self pruning. They should be removed especially the black branches. Leaving black branches on will open up opportunity to infect the trunk, especially in stressed or weak trees. When we have a extremely wet and cool spring we can have issues with fungus in the inner leaves due to high humidity and lack of airflow. We can also have issues with roots being too saturated. One thing we can do for potted and landscape maples is vertical mulch. This adds more oxygen to the roots and helps prevent root rot. Trees usually respond quickly to this technique and you will see a difference in about a week. Sometimes the signs of decline and leaf drop can reverse relatively quickly. When we are having a cool, wet Spring potted maples can be moved to an area of more airflow and sun. But fingers crossed it seems this cool wet period is coming to an end and the heat of July is coming, so it's probably not worth moving now. If fact it may cause more damage than good because the tree is acclimated to it's environment and sun with temperature shooting up to 85F after cool wet shaded conditions will scorch the leaves. But vertical mulching can be done to any tree that seems to be holding too much water in the root zone.
