I'm not sure I understand the timeline you are describing. When was the tree planted? How has the tree done since then (when did you first notice problems)? Have you been consistently checking soil moisture both around and in the rootball? Is the tree properly mulched? Any chance of a picture?

Tree's don't "take a few years to get acclimated to full sun", and what you described doesn't sound like "normal behavior in full sun", especially in northern climates. Something tells me we're either missing some details or something is wrong.

agree with B ..

leaves grown in too much shade.. can burn if moved to too much sun.. but once winter goes by .. the new leaves should be fully acclimated to all sun.. all the time ...

it is VERY COMMON .. for large trees ... with small root mass.. to do this.. until they have grown enough roots to be able.. to supply all the leaves it produced ...

how big at planting.. and how big was the rootball ... and what if anything did you do to the root mass at planting[like pruning winding roots] ...

if you like the location.. i would not disturb the roots again.. by moving it again... i would leave it right there ... and let it grow more roots this fall.. and next spring.. and see if its roots can catch up with its canopy ...

it also does not surprise me.. that a recent transplant.. shed its leaves early ...

all maples.. are full sun plants .... period ... it HAS TO BE A ROOT ISSUE .... especially in WI ....

BTW... most are borderline 5.. the few i have.. all took severe winter damage last winter for me .... in other words.. ma nature reduced the canopy to more better[?] fit the root mass ... lol .....

i would also like to know how water levels were determined... and what is your soil

ken

all maples.. are full sun plants .... period ...

Ken, ken, ken!! Why do you say these things?? I know you have been gardening long enough and have the experience to support the understanding that are very few absolutes in this world. ALL maples are NOT full sun plants and Japanese and other Asian maples in particular are by nature woodland understory trees and do appreciate some shade, especially in hot summer climates.

Sun scorch is very common with many Japanese maples that are grown in a hot, sunny, exposed situation and they do tend to outgrow it with time, maturity and the development of healthy, widespreading root system. But what is described does sound a bit more than simple sun scorch - defoliating completely is a pretty severe reaction to too much sun. I agree there are other issues involved, most likely associated with inadequate moisture. It is possible the original rootball has dried out and soil interface issues are preventing it from rehydrating. Or there could be other root issues, as yet unknown.

Relocating the tree is not a bad idea, provided you address whatever is causing the current problems as well. Since the tree is already defoliated, waiting until later in the season serves no purpose - I'd do it now and give it as much time to re-establish as possible before cold weather sets in. A 1 year old rootball will not be huge and should be quite manageable, especially with a 6' tree. It will also give you the opportunity to examine the roots carefully and make whatever adjustments are necessary to the planting situation. For Japanese maples, that means a very well-draining, moisture retentive, organic soil on the acidic side. And with some afternoon shade if possible :-)

I always find it interesting to read the different perspectives of other members. Gardengal, I had to laugh at your response to Ken. I was thinking the same thing, but didn't want to argue as I'm sure everyone else here is far more educated than I on the subject matter, and I do appreciate EVERYONES opinion. LOL.

I was watering with a hose 1x weekly for about an hour or so on a slow drip, maybe more during drier weather. I don't typically check the soil, I usually just look to see if it's soaking in or running off as my indicator, but in this case the underplanting of lamium is a total groundcover.

In my own admission, I neglected to water it earlier in the season (spring), and it's wedged between a concrete walk, concrete drive, and a flagstone walkway installed in recent years, and surrounded by virginia flagstone as a border, so the tree really doesn't get much "runoff" rainwater. I was told by the nursery that watering it 1x weekly for an hour on a slow drip was probably too much. The bottom line, I think its a combination of too much sun, lack of water, the leaves were first curling on the edges and getting crispy, and more recently dropping after they dried to a crisp. Soil is clay.

My bigger question really is can I move this without killing the tree, and I do plan to move it to a shadier area. I don't recall the exact size of the rootball at the time of planting...I believe the tree was a container planting, not a root ball, and it grew nicely last year.

To answer questions, the tree was planted early spring last year, if I remember correctly. It did ok last year, but then again we didn't have as dry a summer as this year.

My intention is to transplant this to make room for a false spirea shrub which will flourish in full sun.

I'm assuming we should dig as wide as possible to avoid knicking the roots. How deep I wonder?

all maples.. are full sun plants .... period ...

Ken, ken, ken!! Why do you say these things??

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usually i do it.. just to stimulate further discussion ... and a witty response from you ... lol ..

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first off.. she is z5 .... very borderline for most JM's .... SHE WILL HAVE PROBLEMS.. NO MATTER HOW PERFECT HER PLACEMENT... all depending on her little micro-climate ... and any given severe winter .. can kill a JM or knock it back to snow cover ... NO MATTER WHAT SHE DOES .... in z5 ...

whatever .... have a great day.. peeps ...

ken

If you move it, move it when dormant. Dig the rootball larger (wider) than my chart below says you should. Also, go through the text at the link below for tips on transplanting.

Here is a rough/generic rootball size guide for transplanting trees and shrubs. Soil type, tree species, and other factors are not taken into account, but it will give you an idea:

For trunk diameter below 1/2", multiply the diameter by 20 to get approximate rootball diameter.
For trunk diameter between 1/2" and 1", multiply the diameter by 18 to get approximate rootball diameter.
For trunk diameter between 1" and 1-1/2", multiply the diameter by 16 to get approximate rootball diameter.
For trunk diameter between 1-1/2" and 2-1/2", multiply the diameter by 14 to get approximate rootball diameter.
For trunk diameter between 2-1/2" and 4", multiply the diameter by 12 to get approximate rootball diameter.

Here are guidelines for rootball depth:

For a rootball with a diameter of 1', depth should be approximately 8".
For a rootball with a diameter of 2', depth should be approximately 1'.
For a rootball with a diameter of 3', depth should be approximately 15".
For a rootball with a diameter of 4', depth should be approximately 18".

Here is a link that might be useful: Planting a Tree or Shrub