By Mary-Jane Pilgrim, Master Gardener
Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. Plant leaves are most often green because that colour is the part of sunlight reflected by a pigment in the leaves called chlorophyll. However, not all plants are completely green!
Variegated plants can be a beautiful and unique-looking addition to your plant collection. Variegation simply means that the plant’s leaves have both green and non-green parts. Some have shades of cream, or yellow, light green, pink, purple, or red – to name a few. Some plants have a stark white variegation that makes these plants really stand out. Many times, these plants are used to brighten up shady, dim areas or as used as focal points in landscapes or as striking indoor plants. Variegated plants can be the result of engineered breeding or a grower taking advantage of some type of random genetic flaw (chimera).
Leaves of variegated plants occasionally lose their colorful markings and return to plain green. This twist of nature can be frustrating when extra money is spent for the unique foliage markings. Variegated plants often have smaller leaves and are less vigorous than green specimens because the lack of the green pigment means less chlorophyll for generating energy.

Variegated plants can revert or turn green beginning on a stem, branch, or another area. Reverting back to solid green leaves could be a protective way that the plant returns itself back to a healthier form. When this happens, the best thing to do is prune out the affected leaves because if you don’t, the plain green can actually take over the plant because of the increased chlorophyll and vigour as compared to the variegated foliage. If the reversion continues, try to provide your plant with some extra light by moving it to a sunnier location if possible.

Resources
Spotting the signs: Variegated plant reversion
Reversion
Variegated leaves reverting