Unusual Leaf Drop

[missionBonsai]

Hey I’ve had this elm for a couple years, it’s always been pretty happy and healthy. This year it seems to have leaves yellow and drop on a daily basis. I seem to recall the same thing occurring last year but not to this extent.



I have pruned it a couple times this year and it always responded well.





I moved it Sunday thinking it might need more sun, any other ideas? I read it can also mean it needs pruning, do I need to cut back further when I prune?

 

[Shibui]

Pruning is partly about stopping it getting too long but also about shaping the branches. Some branches get cut real short, others can grow longer to fill spaces. I usually trim most growing shoots back to just 2-3 leaves but that depends where it needs to fill out more or less.
As the trees continue to develop I find the need to remove entire sections, sometimes whole branches when growth gets too congested. Initially we all seem to keep way too many branches thinking it will fill the spaces but as those branches all grow they merge together. Trees look good with some spaces.

Yellow leaves dropping can be any number of causes.
Did the tree drop leaves in winter? In warm conditions Chinese elm can hold leaves through winter but then those older leaves drop when new ones take over.
Nutrition. leaves need enough nutrients to stay healthy. If nutrients are not available the tree will prioritise newer leaves and shed older.
Water. ditto as above.
Light can be a limiting factor. Leaves take energy and nutrients to maintain. If they don't return enough food to the tree the tree is likely to decide they can go. If the yellow leaves are deep inside light could be a factor.

Looks like a bit of lime precipitating on the leaves which is likely from your water. have you checked soil pH or water pH?

 

[missionBonsai]

@Shibui thanks for you help… I’m not sure it’s lime, my fertiliser seems to leave that white residue sometimes as well.

Lots and lots of leaves came off today. I’m at a lose maybe I just prune it way back

 

[missionBonsai]