Growth and appearance of whole plant affected, same as with any other tree. Complete lack of bloom unlikely. What, exactly, constitutes "the shade" in this instance?

Hey bboy...and thanks for your reply over in 'shrubs'! By now you may have surmised I am working on that area with the two big alders. Amount of shade is difficult to describe, but medium bright light all day: Zone 23, facing north/ a little N.west. The tree would be not under or between the alders, but next to one and a bit above on a short slope. Also next to the neighbors fringe-leafed,open tree. The roots would be in shade with the mid to top getting a few hours of full afternoon sun and several hours of brightly filtered sun. On the floor of this area it's too dark for Hydrangeas and the agapanthus once there bloomed very poorly.
I love the dark red leaves of the plum and,unlike Forest Pansy, the purple leaf is a sure thing and it is *readily available at all local nurseries. Yes, they are over-planted and have their issues, but love that color and availability.
I do really appreciate your input. I have wrung my hands in indecision too long and need to get moving on this!
*a vicious circle? we buy what's available and they stock what we buy? No fun reading and researching and seldom finding anything but same-old in nurseries.

Maybe try some California natives that grow in similar situations with the same species of alder. Since California has a rich native flora there are growers who specialize in these, put them on the market. And publicly accessible display gardens that demonstrate their use.

Nice thought, but most natives are not appealing to my east coast sensibilities, and I'm too old to be changing my tastes :>) :>/
I guess that's not PC( being native unfriendly), but just cannot be helped. Hope I can still get help and advice.

Non-natives require more water and very soon your water bill will be very different. And east coast Prunus will start dying as a result. That will change sensibilities in a hurry.

Nonetheless, Prunus in general don't thrive in shade.

Dan

"...Growth and appearance of whole plant affected, same as with any other tree." So, bboy, then a tree's growth is influenced by amount of shade but not shrubs...or at least not rhapheolepsis, or not so much? The shrub might be less dense, and that's okay as long as the height isn't terribly stunted.
Dan, I doubt my water bill will be seriously impacted by one or two new patio type trees. The trees are not native, but the over-planted, seen everywhere, boring ornamental plum. You believe this type will not thrive in shade? I like them for their deep purple leaves. Any bloom would be icing on the cake. TIA to you both!

Look for commonly sold 'Krauter's Vesuvius'. It was selected in California, has good color retention in hot summers.

Yes, bboy! That's just the one I'd planned. Thank you so much for all your help.

I didn't claim your water bill would increase due to a tree being planted. I stated your (and many others' there) water bill will likely go up substantially and non-native landscapes will suffer as a result.

Dan