Q.Little Gem Magnolia Blossoms But Wilts Immediately
We planted it last August (2019) in well draining soil. We live in the Pacific Northwest, the climate never gets too cold or hot. Not sure if we are over/under watering? We’re using a soaker hose once a week.

Certified GKH Gardening Expert
If you are watering on a schedule, then it is most certainly overwatering, which leads to infection.
The tree is quite drought tolerant and will want the soil to dry very thoroughly down to about 3 or 4 inches between waterings. You will need to confirm that it is dry down to this depth before watering, or not water at all. Usually rain water is more than enough to keep it healthy.
At this time, you will want to treat with fungicides, and reduce watering to, only, when necessary.
These articles will help:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/special/organic/biofungicide-information.htm
https://www.gardeningknowhow.com/garden-how-to/info/homemade-fungicide.htm
https://www.gardeningknowhow.com/garden-how-to/info/applying-bactericide-to-plants.htm
https://www.gardeningknowhow.com/ornamental/trees/magnolia/magnolia-tree-care.htm