They're beautiful. I agree, hoyas come in the most fantastic color combinations! So do succulents. (I see that's your favorite forum.) I never knew until I came to GardenWeb what an amazing range of color plants came in. I've learned so much. I am an artist too, but I haven't been, er, arting very much lately. But I think I'm getting inspired to get back into it. :)

This is a natural change most likely due to the increased red in the colour temperature if light this time of year. Given bright light these plants will display this colour all year.

Mike

I am not an artist, but I have an eye for what is very artistic, and the ways of plants always presents to me a beauty that can hold my attention longer than any painting or sculpture.

Adding high phosphorus fertilizers will also keep the reds and pinks in foliage longer.