As you can see from the lead photo of this large hedge of variegated buckthorn (Rhamnus a. ‘Variegata’) variegated leaves can be a useful tool to add beautiful, easy contrast to your plant design.
In this short post, take a look at the “hue effect” variegated leaves play in visual contrast to different leaf color -especially straight green or blue colored plants. But first…
Q: What is variegated foliage?
A leaf that has more than one color. Think of two toned foliage, blotched foliage, striped or bordered with a lighter color than the rest (vice versa) – Wikipedia
Smaller variegated leaf sizes in mass planting provide an excellent way to contrast varying shades of green and colored foliage. To be zoomed out (viewing at a distance) variegated foliage often appears light green, light blue or even a yellowish green. Take a look below…
Here are some visuals to demonstrate this talking point

Lavandula x allardii ‘Meerlo’ – Close-up
Now take a look of this plant, in the garden, used as a low planting…

Lavandula x allardii ‘Meerlo’ as low hedge. Oakland, CA (Distance photo)
See how this variegated lavender is impactful and creates year-round contrast in this planting design?

Prostanthera ovalifolia ‘Variegata’ with purple Loropetaum. (Above, center plant, close-up)

Prostanthera ovalifolia ‘Variegata’ – simple planting contrast. Piedmont, CA. (Distance photo)

Agave attenuata ‘Ray of Light’ – This succulent punctuates trailing rosemary. Tiberon, CA

Contrasting green privet hedge with low variegated Pittosporum. SF, CA
Conclusion
With this post, I hope you got the idea that using variegated foliage is a powerful way to create contrast or complement foliage in your garden design.