You will rarely see a good blue in the sun... blue coloring in hostas is actually a wax coating over a green(chlorophyll) background.

Maybe the best example of this is from the Halcyon family. Halcyon is a nice wax blue. June is a sport from Halcyon with the blue wax genes intact. On the other hand, Devon Green is a green sport from Halcyon that lacks the wax gene and is a shiny green.

June Fever, the very bright yellow (in Spring) with a thin green margin is bright and shiny precisely because it is not, as we were originally told, a June sport but rather a sport from Devon Green - it lacks the wax gene and is thus shiny.

In the sun, the heat, or after a lot of rain and overhead watering, the waxy blues will lose their wax and become green. It seems that some cultivars will generate more wax, while others never seem to develop it again in the same season after it melts away.

The Halcyon clan has been the best at holding blue into the heat of summer. El Nino and First Frost both are still a good blue with the added advantage of crisp white borders. Touch of Class holds up very well in sun. This family has the added advantage of standing up longer into the fall as well. They often look good after many of the other hostas have died back from the first frosts.

A surprise for me is how well Kiwi Full Monty, a striptease sport with bluer leaves, holds its blue into summer. And the new flushes will be very blue even if the older ones have lost their wax.

So, yes... there are some general rules - but there are plants in each category that do just the opposite.

usually yellows get yellower in more sun and more chartreuse in more shade, the simple reason being the plant needs more chlorophyll to grow in lower light conditions. But there are exceptions - yellow plants that get more greenish in sun.

And among the green ones, there are probably more that become less green in bright light and darker green in lower light - but there are some that reverse this.

I've never seen an exception in the blues - a plant that gets bluer in brighter light.

I sometimes plant blue plants in the sun - though they won't look as good, they will often grow much faster, allowing me to get some extra growth on them before moving them into the shade.

the general rule would be:

MOVE THEM TO A NEW LOCATION IF THE COLORATION BOTHERS YOU

ken

idiothe, your reply was thorough and excellent, thank you very much! That was great to know about the blues being from a wax, and that sun alters that significantly. I have three TOC, two still in pots, and I think they are my favorites, so far. Good to know about them holding their color well. I learned an awful lot in just a few words, thank so much!!!

Ken, I am disappointed. You, too, seem a valuable resource of information for newbies like me, but you offered up something utterly useless to me for when I am trying to choose cultivars for specific locations. On top of that you "yelled," and that is just rude. :o(