Regarding variegation

Regarding variegation

Hello everyone, I got two variegated peppermint plants in April, and they've grown pretty well. However, up till now, only a small portion of one of the plants have acquired the variegation which was supposed to come with it, even though both pots are placed at the same place, and watered with the same frequency etc. Would anyone be able to share how I can induce the plant to produce more variegation? Thanks in advance for any help.
Red Lily Beetle alert.

Red Lily Beetle alert.

Here we are.

Here we are.

A tree/bush from Mt. Vernon – What is it?

A tree/bush from Mt. Vernon – What is it?

Don’t you love spring?

Don’t you love spring?

Can anyone tell me what kind of flower this is ?

Can anyone tell me what kind of flower this is ?

zebra print.

zebra print.