Q.Royal Raindrop Crabapple In Part Sun
We were advised by our nursery that this type of tree would do well with a partial sun position in our backyard. However your article says it must have full sun. Also not sure how well drained is the soil since two trees have died in roughly the same place in the past 18 months, a pine and a river birch. What chance does this crab tree have and what should we do to give it the best chance. It is beautiful even in June. Thank you.

Certified GKH Gardening Expert
It sounds like your soil is diseased, or the tree receives too much water, without being allowed to dry out between watering, which, in turn, causes disease.
I would have your soil tested, thoroughly. This article will help:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/test-soil-for-pests-and-diseases.htm