Can anyone tell me how long it takes Fatsia japonica to grow to maturity where it can produce flowers and fruit?
Thanks!

It all depends on the climate and care. Remember that they come from parts of Asia that have very warm, wet and humid summers; that is when they grow fastest.
In the PNW it takes many years. In Coastal California maybe 3 years with good conditions and loads of fertilizer.
Utah? No idea.

Thanks Iochroma!

I have had in my garden for many years and flowering after the 3rd - 4th year in my garden zone 8b.
Flowers form and round seed heads. By summer end. I cut them down every year and trained as a shrub in my garden. They are Japanese Aralia.
They need bright, indirect light to encourage bud formation, humidity and consistent conditions to flower. To ensure optimal soil, water, and pest control to keep plants happy , and fertilize in early spring.