I have had a variegated euonymus plant for several years. Each year when the leaves come on, I get one branch that is only white. It is not sick, it simply has white leaves. Would you be able to give me any information on this?
Generally, variegated hybridized plants will revert to their green parent so having yours consistently grow white is quite interesting. In botany, we call this phenomenon a “sport”. It is a growing part of a plant that shows morphological differences from the rest of the plant. Sports can differ in their foliage color or leaf shape, branching structure, flowers and even fruit. The cause is generally thought to be a genetic mutation that happens by chance. Some sports can be grown on to become a new variety of the species.
In this case, the probability is that your plant had a Euonymus parent with dominant white leaf characteristics which was crossed/hybridized with a green leafed Euonymus to produce a variegated leaf variety. What you’re seeing now is some of those white genes re-emerging. For the general home gardener, we recommend that these mutant branches be removed from the plant so that it remains growing true to the variety you purchased. That being said, it would make for an interesting experiment to see if, after cutting the white branch off, you could take the cutting, propagate it successfully and see if it remains white.
Hope this helps.