It's bright yellow in full sun. The more shade it gets the more green it shows.

that is the typical answer for any yellow plant ...

green tissue converts sunshine into energy...

in full sun.. a yellow plant can thrive and prosper when yellow..

as the light significantly goes down.. the plant has to turn green.. to keep the level of photosynthesis the same.. so it greens up to increase the process..

full sun is usually 8 hours a day... and not significantly at dusk and dawn.... so 8 strong sun hours....

welcome to the forums.. add your location in every post.. or add it to your name.. in this case.. sun in maine is significantly different that FL sun.. so you need info from peeps in your type of area..

ken