No, they are usually just one color. I planted those same two colors, plus a red one under my dead hibiscus bushes. I'm trying to get them to grow on the dead hibiscus to create shade where there now is none.

It seems to me the Heavenly Blues have a more red cast before they unfurl and after they dry and shrink on the vine... could they sometimes turn to that purple "early"? Today, in the overcast and drizzle, I had a blue full bloom and a purple that was open but beginning to fold - on the same vine, a few inches apart. When I lifted the strand to photo it more clearly, the purple fell off. There went my photo proof!

I think i have had this happen too, i cant find my post about it.

I did find this though

http://homeguides.sfgate.com/can-ph-affect-color-plants-76416.html

Ok i found it... i had to use google, search in the forums is a PITA

https://www.houzz.com/discussions/something-must-be-lacking-dsvw-vd~4412362

So strange, because there is a blue morning glory that stays blue. My neighbor had one that reseeded itself every year, and it was always blue. I know the native ones that are pink and purple are always either pink or purple. I gathered some seeds this year from a fence nearby, but I lost them.

Interesting about those several plants cross-pollinating. Thanks!

I've been watching the "Bones" TV series, Season 10. Dr Hodgkins injects (his) blood into hydrangea flowers and spins them so the centrifugal force will force them to change color (the time it takes to change is crucial to solving the murder case). Did any of you see that and think it was in any way plausible?

10 a.m. today

5:38 p.m. today

So, this Heavenly Blue blooms blue but ends blue-purple. Do your morning glories change color like this?

my morning glories are just starting to climb. One of the blue ones bloomed when it was still tiny, but no other blooms. I should have red, purple and blue. We'll see. I don't think many of the red ones came up.

Flower colors can certainly fade, or darken with age.

And it can also be difficult to see 2 plants twined together sometimes.

OK Final Answer

https://www.nytimes.com/2016/03/03/science/a-quick-colorful-change-for-a-morning-glory.html

I just wasn't asking the right question at the right place.

Started mine from seeds always had different colors