My experience with growing Petra in Shade shows the best leaf color with nice hues of orange and pinks with more pronounced veining of the leaves. Full sun grown Petras show lots of yellow color and have less pronounced veining. Overall Petra performs well in sun to shade conditions.
For me..I see that. The change from red to yellow in full sun. But,my climate wouldn't put any growth on it in shade or part shade. Like Cycads that turn deep green in the shade in Florida,in the bay area they wont let out a frond under that lighting. Get them into sun...and they are winners.
And,I'm getting conflicting testimonials of Crotons like "Mammy" (Its the 21st century,time to drop that name isnt it?) being good in California and others saying its the worst to try.
Ok,2 of 3 Petra in a pot died by spring. The largest was defoliated but has come back somewhat- leaves 1/4 the size of last summers. But then,so has Mammy with 1/3 size leafs that slooooowly turn red. Or it might be a Mammy look alike as suggested here by a Croton expert.
I must really underestimate how cool we are compared to hot summer or tropical climates. I feel hot at 84f.just right at 77-80f..but my real tropical's just mosey along in the SF bay area.
Petra and Mammy gave out at the end of December. Shocking since they looked fine,I covered for a predicted 32f...and they just wilted like boiled lettuce. That much wilt,that early in winter is sure death.
I might try again. I got two years out of Petra,one and a half out of Mammy, and if I had put both on my front porch for winter....I might still have them. Now,I know.
2018..I tried Petra again...its done 2 summers and 2 winters outdoors..going on its third summer. That's the good new. The bad news is if I don't put it in a small greenhouse this winter of 2020- 2021..its going to die. July and its barely leafed out. Its the very definition of marginal in the bay area. Funny how the spiral is so slow.