I have a two year old green laceleaf waterfall japanese maple in my front (west facing) garden that gets full afternoon sun. Up until now it’s been healthy — but it has only leafed in about 30%.
Before this tree was in its spot, there was another (red) laceleaf weeping jpn maple — but it had to be removed due a fungal infection. Before that, it was a beautiful old cherry that died from a bacterium.
Could the earlier plantings be affecting the new tree? Or is it Toronto’s harsh winter? There is another, older waterfall on the street in much the same condition. But others, in more sheltered places doing well.
Do you have any idea why this is happening? or ideas on how to help my tree?
This is a difficult questions but Japanese maples are highly susceptible to damage from fungal infection, including foliage discoloration and loss, structural damage, even death. Infections should be promptly diagnosed and treated to prevent irreparable damage.
You might want to have your soil tested for the presence of the fungus from the previous tree.
And, here is a link to a similar problem on the Toronto Master Gardeners site that you might find helpful.