Japanese Maple problem leaves
We have a Japanese Maple, not sure of the variety, but the leaves look like the picture on the maple forum page. The tree is about 18 years old and has grown to about 8 ft across and about 3-4 ft tall. The tree appears to be healthy and grows each year, but in the middle of the summer most of the leaves turn light brown at their ends (appear dried out) and in the fall instead of turning a nice red, most of the leaves continue to have a burned on the ends look and even the portion of the leaf that is not "burned", does not turn red. Some of the leaves on the lower portion of the tree, do not get the burned ends and do turn red. But overall, the tree has a disappointing look to it for much of the year compared to others in our area.
Being next to a lawn that gets well-watered, we think the tree is getting sufficient water. And it is sure getting a lot of water now... here in Seattle. The ground is sloped steeply away from the tree on the side opposite from the lawn and the slope is covered with ivy.
Any ideas on what's wrong with the tree and/or how we can get the tree to look the way we think it should, would be appreciated.