Why Doesn’t My Mahonia – Winter Sun – Flower

Question

It was planted in the autumn 3 years ago & seems to be flourishing but its never flowered

Answer 1

You can check on your plant's growing conditions based on the tips in this article:
https://www.gardeningknowhow.com/ornamental/shrubs/mahonia/grape-holly-plant-care.htm
I'm not clear about your location, but the Oregon grape is native to Oregon where the soil is rich and moist. Your soil's pH should be between 5 and 8, so you may want to do a soil test. https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm