Why do the tips of my Japanese maple go crusty

Question

I had it in the ground for a few years and it hardly grew, hard ground, clay soil. I moved it to a big tub looks healthier but still crusty leaves.

Answer 1

That could be sun scorch. Is your maple in full sun? If so, you can move the tub to a part shade location.

https://www.gardeningknowhow.com/ornamental/trees/japanese-maple/japanese-maple-care.htm