PS- this tree gets direct afternoon sun for 4-5 hours, but no morning sun.

smcstl, you have to post pictures of it in the fall for me. I've been curious about its late colors. All my trees drop their leaves so early.

Turning yellow like early fall colors from stress or drying up like baked in the sun?

I'm always concerned about root temperature of trees in pots, the whole soil mixture thing also confuses me. Is the pot of yours in the sun as well? Have you been getting the random downpours where it might be flooding out? Is the pot black or dark colored?

My thing is planting unbelievably fresh grafts and small trees right into the yard inside small fences lol.

I'll tell you one thing great about this maple, it's durable. I have had one in a container for 4 years, The container is a copper pot about 4 gallon. This tree made it through the Easter freeze of 07,(I lost 32 other maples) and my teak double rocker fell on it in a high wind and smashed it. The tree came back and it looks very cool with interesting trunk shape and it is putting on new growth all year. It is about 3 foot tall now.

My tree is in a rather large pot. I would say it is easily 30 gallon if there is such a size. Let's put it this way, It takes 2 men to move the pot alone with no dirt. Moving the pot now would require a forklift with the tree and dirt in it. I am thinking that it is cooking in the sun. We have had several weeks in a row where the heat index was well above 100 F. I have ordered shade cloth and will be putting that up soon. With that said, we have has several thunderstorms where it rained alot, so it could be overwatered too.

Too much heat is very likely the problem. While Shishigashira is one of the most sun-tolerant Japanese maples, it will still crinkle and burn with too much sun or a lack of water. Maples in pots are usually especially stressed since their roots have a harder time cooling down and can't access water from a huge area.

If possible, shade the maple some during the hottest stretchs and make sure it receives ample(every other day at the least) water.

Goodluck.

-Will