Dear Jim:
Always great to know of you. Yes, variegation is harmless and there
are not known cases of their spread to other plants, being mostly genetic.
There is range of fantastic variegated plants. There are however forms of
variegation caused by virus in Abutilon, Aucuba, Ampelopsis, Chlorophytum
that are not contagious to other plants even in their own genera. I had a
however a severe virus case in Aspidistra elatior 'Variegata' the symptoms
being masked by the plant's variegation.
Regards
Alberto
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