A: The good news is that nothing is wrong with your maple.
Japanese maples give great color in shadier areas of our landscapes, but they’re very much a ‘Goldilocks’ plant, as in they like everything to be just right to provide the best show. The summer’s heat drives some of the leaf color out, as does the fact that we (by necessity) plant Japanese maples in partial shade to counter that heat. Japanese maples like sun but can’t tolerate the heat during our 100-degree summers, and afternoon sun is more than they want to take.
The following will improve your maple’s color, helping it keep better red color further into the summer.
Morning or dappled sunlight – A red maple in deep shade will not be as colorful. New growth will still emerge the proper red color, but that color will fade back to green faster. It’s still reasonable to plant a Japanese maple in deeper shade but expect red types to lose color faster each spring. Consider planting one of the bright green leafed types in darker locations! Bright green shows up well in deep shade, where red colors would often be muted or less noticeable.
Plenty of summer moisture – Regular irrigation is a must. Newly planted Japanese maple leaves often get burned tips the first summer, but better irrigation will minimize this until the plant’s better established.
Age – A healthy, established root system helps the plant stay comfortable further into the heat.
New growth – Red-leafed types will emerge red, even for growth later in the year. It’s common for us to have some new growth in the late summer into the early fall, as temperatures lower from their peak, which will add accents of red to the plant.
A mature Japanese maple anchoring a bed is a beautiful thing, sure to inspire comment and appreciation.