you are in a hot zone but unless you have gotten really hot temps this doesn't sound right especially if it gets afternoon shade...I have heard that heavy fertilization can cause reds to turn greem ...did you fertilize it or was it planted in a previously fertilized area??? Other than that and I am not totally sure that would cause it ...you may want to think twice that it is a CC...maybe mistagged the or maybe a seedling not true to it's lineage ( is it grafted?? ...look for bulge probably half way up the trunk on CC) David

Man, I'm having the same issue with an "Ever Red" dissectum... I was assured by my wholesale nurseryman that the tree would turn gorgeous red, but it is still green/bronze. It is in morning sun, afternoon shade. Seems I've got to replace this for my client, who wants a solid red jap dissectum maple. I was figuring "EverRed" would be Red! My fault - I should've not been naive in thinking it would change color drastically at the client's garden.

After this HOT summer I am TOTALLY rethinking my post ... and it may be even be the correct cultivar that is green in TX even in May since it is HOT down and I now think most red JM's will NOT keep their color in the summer in hot climates...VIRTUALLY none of mine did this summer...except for a few that were in alot of shade but not total shade...This went for both dissectum and broad leaf varieties.Some varieties like the tamukyama and bloodgood and kasagayama, Emporer1 and my beautiful Beni Otaki said to hold their red color well throughout the summer were TOTALLY green by mid july... in fact the ONLY full sun cultivars that stayed red in full sun were my Shojo Nomura and my fire glow ( which had some rather severe leaf scalding)...and many are just now turning their fall red. If this happens in central Il.( hundreds of miles NORTH) during a hot summer I don't see HOW you can ever gurantee any JM to be reliably red throughout the summer in GA or TX even in partial shade...I'm sure there are exceptions and humidity and soil type plays a part but if I were "in the landscaping biz" I surely wouldn't want to guarentee it...unless you like constantly replacing cultivars. There is also the FACT everyone has their own idea of red and to some a "redish" summer color would be fine to others they would pitch a fit!!! I think you CAN reliably guarentee certain JM cultivars to be RED either dark or bright, in spring and fall and maybe early summer depending on where you live ...but NOT all summer in southern climates or during unusually hot summers even in northern climates. David

Here, despite our cool summers most purple ones go bronze in full hot sun (humid, well watered sites give a much better result) and greenish in full shade. Where there is not an irrigation system, lake or other influence keeping the whole site humid all summer you have to split the difference and plant in partial shade to get the best color retention.

I was presented a lace leaf Japanese Maple as a Crimson Queen by the nursery worker although it was clearly labeled as a Lace Leaf. Apparently, the two are quite similar but, the lace doesn’t hold its crimson color throughout the year like the Crimson Queen. I bet yours had been mislabeled or misrepresented as mine was.

Lace Leaf is not a cultivar name but a description of the degree of dissection of the individual leaves. In fact, laceleaf and dissectum are terms used interchangeably to describe these very delicate looking, lacy leaves. Crimson Queen is most definitely a laceleaf cultivar, as is the Ever Red mentioned previously.

The issue of red leaved Japanese maples losing color in summer is an ongoing one and in no way indicates the tree is necessarily mislabeled. If provided with suitable conditions, most red leaved forms (dissectums OR palmate leaves) will bronze out or turn a greenish shade. Some cultivars will hold their color better than others but the phenomenon is VERY common!

It is also important to remember that JM's will typically go through at least 3 different leaf colors during the growing season - early or leaf out color, midseason color and fall color. And they can be very different from each other.