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Variegation on the Green Theme - Part One

© Marge Talt

Part One - Chalk to Silver

There's nothing wrong with green. Green, from spring's acid awakening to late summer's dusky hue, is the color of life on this planet. But, green, like life, can use a little spice. Variegated foliage is spice for the shady garden, where flowers are few in mid-summer.

Chloroplast The cellular bodies that produce and house chlorophyll.

Green is the color of most plant foliage because of the dominant green pigments (bluish-black chlorophyll a and yellowish-green chlorophyll b) in the chloroplasts located inside the cells of plants, absorbing sunlight which enables the process of photosynthesis. The sun's energy strikes the chlorophyll which starts a reaction producing carbohydrates that plants, and the creatures that eat them, use for food.

Chlorophyll masks the other pigments - beta-carotene (red-orange), xanthophylls (yellow) and carotenoids (red-orange or orange) - contained in leaf cells, which are only apparent in most green leafed plants either as they unfold or as they senesce at the end of the growing season.

While we look at variegation as an enhancement to foliage, generally it means that some random mutation of DNA has resulted in imperfect or absent chloroplasts. Variegation can also be caused by mineral deficiency, a viral infection or some environmental reason. Whatever the cause, it means there is some obstruction to the plant's ability to create food for itself, hence the fact that most variegated plants are not as robust as their green brethren.

There are notable exceptions to this rule. Disporum sessile 'Variegatum' (Japanese fairy bells) is one of these. While not invasive, its questing rhizomes will move it through a bed or border where they will pop up unexpectedly, sometimes in the middle of a clump of some other plant.

These graceful, slender plants are welcome in my garden wherever they show up. How can you resist a leaf that looks like it was painted by a band of garden elves?

To most of us gardeners, and especially all of us variegated plant nuts, variegation means anything but green, including foliage and stems that exhibit white, reds, yellows, pinks and any combination thereof. Research has indicated, however, that to the scientist, variegation refers to distinctive patterns of green and white on any plant parts that normally contain chlorophyll.

White is the absence of all pigment in cells that have no ability to photosynthesize. A totally white plant is not long for this world; it will soon starve itself to death. An occasional totally white leaf on a variegated plant will persist because the green portions of other leaves and stems are producing food for the plant. The absence of pigment does not mean dull by any means. Plants in this category add highlights to the shade, from chalk to cream to silver and everything in between.