|We've purchased a Japanese maple,|
That spot sounds good if you can amend the soil somewhat. Japanese maples need some shade to do well. Morning sun and afternoon shade is best.
Give it a soil enriched with plenty of compost and good drainage. Mix several inches of compost into the soil in a large (10 foot wide or more) area. A raised planting bed is also good but unless the area is poorly drained is not necessary. Then dig a hole for your maple that is twice as wide and only as deep as the root ball. Unwind or cut any circling roots in the container. If you unwind them make sure and dig an extension from the planting hole to accommodate them. Don't just wind roots around in the hole.
Set the plant at the same level it was growing in the container. Put the soil from digging the hole back in firming it around the root ball. Then water it in well to settle the soil. Keep it on the moist side especially during the establishment year.
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