Question: Explain Variegation in Ivy (x): possible changes roadmap

There are no records of Hedera helix cultivars which originated from mitotic recombination. Hedera helix 'Buttercup' has entire yellow leaves. Peter Rose states that 'Buttercup' is a nuclear mutation because this cultivar comes true to type. This could mean that 'Buttercup' is a yellow leaved mutation as described by Ben Zonneveld. There is no record of a variegated sport that originated from 'Buttercup' (caused by mitotic recombination).

Hedera helix 'Sterntaler' is another cultivar with entire yellow leaves. According to Ingobert Heieck yellow shoots of 'Goldstern' can be propagated vegetatively. He named this new cultivar first 'Goldstern 2' and finally 'Sterntaler'. Only yellow leaved mutations will survive vegetative propagation. This could mean that 'Sterntaler' is a yellow leaved sport of the variegated cultivar 'Goldstern' which in turn originated from an unnamed yellow leaved mutation by mitotic recombination. Pictures of 'Sterntaler' show a light green leaf colour so I'm not sure.

Green leaved species roadmap to variegation:

* albino chloroplasts
** green chloroplasts
*** lethal type of chloroplasts in a chimera with viable chloroplasts

Sources: Hedera sorten, Ihre Entstehung und Geschichte dargestellt am Sortiment der Gaertnerei Abtei Neuburg, Brueder Ingobert Heieck OSB, 1980, Gaertnerei Abtei Neuburg; The Gardener's Guide to Growing Ivies, Peter Q. Rose, 1996, Timber Press; Variegated trees & shrubs, Ronald Houtman, 2004, Timber Press

The next time it's time for a recap.