Hardest solid color? One that doesn't shift or change.
Yellow, burgundy, and dark purple generally do not shift or fade in my field. Red is a hit or miss with fading. I've gotten some unique solid shades of red/orange that are highly pigmented that I'm watching. I think they turn more orange in the fall. I'll watch more closely this season.
If I get a true solid white it generally does not change, but I've had some give me a lavender hue in the fall.
I've been looking for lighter hues of all the solid colors. Cream (very light yellow), medium pink (darker than a bridal blush. Eye Candy from the UK is the correct color), pastel orange aka peach, and a light purple (deeper than lavender).
With the exception of cream, the other colors always seem to tag along with another prominent color so the pigmentation presentation is filtered and not a fully saturated color.
These filtered and layered colors might read light purple or peach but these colors seem to shift with temperature and sunlight.
This one seems to be a stable light purple.
This peach surprised me and didn't shift this fall. It's a first year seedling planted closest to the hedgerow so more plants and a sunnier location might prove otherwise.
