I alternate between a couple of them; always with added vinegar due to my irrigation water pH of 9+. Most often it is Liquid Gold (Master Nursery/EBStone) [15-6-3] Then, Foliage Pro [9-3-6] And lastly once every 2 months (and because i bought a bunch of it years ago-cheap) Miracle Grow - very weak solution. this is not a cheap method, but its the only way i have found to feed the citrus during the heat season and keep it growing without using excessive water. [there are improvements and changes that i need to make to the irrigation, but unable to attack that project at this time. So i am stuck with what i have for now]. I used to mix it all in a watering can and apply to pre-wet soil. I mixed for a 1 gallon amount, but in a full 1.5 gallon can (so a bit weaker solution). 1 can per tree (or more if taller than 6ft.). Today i tried a sprayer and believe it worked well. I used a Hudson hand-held sprayer that has a metering knob. I could turn the liquid addition off, and then adjust up to 1 Tbsp /gal. This turned out to be a much faster and more convenient method (45 citrus trees) so i think i will stick with it. -George

Was your tree in pot when you bought it? Potted trees often are root bound and hold tightly to the medium they were planted in. Did you spread out the roots before you planted. That could be why the roots cannot fully function. Like others say, over or under watering could kill a tree. I feel that your issue is the roots not functioning properly.

Where are you and what kind of maple? My decade old Acer rubrum is mostly free range. It last got watered in 2012 during the historically (well, back to the dust bowl era) hot dry summer.

The color also looks too yellow to be right. From the photo, it looks like it may have been planted too deep since I cannot see the root flare, the part of the trunk where the base of a tree broadens slightly, though it might be just hidden by mulch. Or it may have come from the supplier planted too deep. IME pin oaks are reasonably happy with OH soil. Mulch shouldn’t be against the trunk, so pull that back. Ideally mulch will start a few inches from the trunk and go out to the drip line of the tree on a small tree such as this to reduce competition from grass. I would pull aside the mulch and soil until you find the root flare to see how deeply it is planted compared to the flare. Have you done a pH test? What has the weather, particularly rain, been like this year compared to usual?