Hibiscus advice please.

Hi everyone, I bought a hibiscus syriacus yesterday from the half dead section in our local GC. Having tried to read up on these yesterday I'm struggling to find the correct information as the label says it's a mix but the flowers are pure white with no colour like the mixed ones online I have space in the garden in a border and have a paved patio area in full sun this can go nicely in a pot. As you can see some of the leaves are very yellow. I'd normally associate this with over watering? Any advice would be welcomed. Thanks in advance.

 

If it says mixed on the label I m guessing it means that the batch of plants that were bought in by the store were mixed colours, that way they can just use the same label.

It's been in its pot too long and starved would be my guess for the yellow leaves.
Think it would prefer growing in the ground rather than a pot.

 

Ah I see @pete, great thank you