We recently planted 2 beautiful little maple trees in our front yard and one is not doing well. It is a small Acer Mikawa Yatsubusa. There are several branches with dried up leaves, especially towards the ends (see picture). We planted it about 3 weeks ago and have watered about every 3-4 days. We planted it with mulch as recommended to help with drainage. We're not sure if maybe it's getting too much or too little water or if something else might be to blame. It wasn't a cheap tree and we really want it to thrive, especially as we have a matching one on the other side of the yard that is doing rather well. Any advice?

Where are you? What kind of exposure does your tree have? Ideally, you would water the tree every day for the first week and then taper off, watering when you have less than 1" of rainfall per week.

Don't give up hope, Japanese maples are surprisingly resilient. I get a lot of these from my cousin (his scratch n dents) and just water them in well and consistently then wait until the next spring to see what is growing or not. Once you determine a branch is really really dead, just snip it out and let anything still alive grow. Good luck.

It needs well drained soil and prefers acidic to neutral soil.
Dig down and see how the soil is draining.